title:
A 16-bit Coherent Ising Machine for One-Dimensional Ring and Cubic Graph
  Problems

abstract:
  Many tasks in our modern life, such as planning an efficient travel, image
processing and optimizing integrated circuit design, are modeled as complex
combinatorial optimization problems with binary variables. Such problems can be
mapped to finding a ground state of the Ising Hamiltonian, thus various
physical systems have been studied to emulate and solve this Ising problem.
Recently, networks of mutually injected optical oscillators, called coherent
Ising machines, have been developed as promising solvers for the problem,
benefiting from programmability, scalability and room temperature operation.
Here, we report a 16-bit coherent Ising machine based on a network of
time-division-multiplexed femtosecond degenerate optical parametric
oscillators. The system experimentally gives more than 99.6 % of success rates
for one-dimensional Ising ring and nondeterministic polynomial-time (NP) hard
instances. The experimental and numerical results indicate that gradual pumping
of the network combined with multiple spectral and temporal modes of the
femtosecond pulses can improve the computational performance of the Ising
machine, offering a new path for tackling larger and more complex instances.


title: Context-dependent feature analysis with random forests

abstract:
  In many cases, feature selection is often more complicated than identifying a
single subset of input variables that would together explain the output. There
may be interactions that depend on contextual information, i.e., variables that
reveal to be relevant only in some specific circumstances. In this setting, the
contribution of this paper is to extend the random forest variable importances
framework in order (i) to identify variables whose relevance is
context-dependent and (ii) to characterize as precisely as possible the effect
of contextual information on these variables. The usage and the relevance of
our framework for highlighting context-dependent variables is illustrated on
both artificial and real datasets.


title: Markov State Modeling of Sliding Friction

abstract:
  Markov State Modeling has recently emerged as a key technique for analyzing
rare events in thermal equilibrium molecular simulations and finding metastable
states. Here we export this technique to the study of friction, where strongly
non-equilibrium events are induced by an external force. The approach is
benchmarked on the well-studied Frenkel-Kontorova model, where we demonstrate
the unprejudiced identification of the minimal basis microscopic states
necessary for describing sliding, stick-slip and dissipation. The steps
necessary for the application to realistic frictional systems are highlighted.


title: The Myers-Steenrod theorem for Finsler manifolds of low regularity

abstract:
  We prove a version of Myers-Steenrod's theorem for Finsler manifolds under
minimal regularity hypothesis. In particular we show that an isometry between
$C^{k,\alpha}$-smooth (or partially smooth) Finsler metrics, with $k+\alpha>0$,
$k\in \mathbb{N} \cup \{0\}$, and $0 \leq \alpha \leq 1$ is necessary a
diffeomorphism of class $C^{k+1,\alpha}$. A generalisation of this result to
the case of Finsler 1-quasiconformal mapping is given. The proofs are based on
the reduction of the Finlserian problems to Riemannian ones with the help of
the the Binet-Legendre metric.


title:
Nonlinear pulsations of stars with initial mass 3 M_\odot on the
  asymptotic giant branch

abstract:
  Pulsation period changes in Mira type variables are investigated using the
stellar evolution and nonlinear stellar pulsation calculations. We considered
the evolutionary sequence of stellar models with initial mass 3 Msol and
population I composition. Pulsations of stars in the early stage of the
asymptotic giant branch are shown to be due to instability of the fundamental
mode. In the later stage of evolution when the helium shell source becomes
thermally unstable the stellar oscillations arise in either the fundamental
mode (for the stellar luminosity L < 5.4e3 Lsol) or the first overtone (L > 7e3
Lsol). Excitation of pulsations is due to the kappa-mechanism in the hydrogen
ionization zone. Stars with intermediate luminosities 5.4e3 < L/Lsol < 7e3 were
found to be stable against radial oscillations. The pulsation period was
determined as a function of evolutionary time and period change rates \dot\Pi
were evaluated for the first ten helium flashes. The period change rate becomes
the largest in absolute value (\dot\Pi/\Pi\approx -0.01 per year) between the
helium flash and the maximum of the stellar luminosity. Period changes with
rate |\dot\Pi/\Pi| > 1e-3 per year take place during approx 500 years, that is
nearly one hundredth of the interval between helium flashes.


title:
Learning the Curriculum with Bayesian Optimization for Task-Specific
  Word Representation Learning

abstract:
  We use Bayesian optimization to learn curricula for word representation
learning, optimizing performance on downstream tasks that depend on the learned
representations as features. The curricula are modeled by a linear ranking
function which is the scalar product of a learned weight vector and an
engineered feature vector that characterizes the different aspects of the
complexity of each instance in the training corpus. We show that learning the
curriculum improves performance on a variety of downstream tasks over random
orders and in comparison to the natural corpus order.


title:
The order of the automorphism group of a binary $q$-analog of the Fano
  plane is at most two

abstract:
  It is shown that the automorphism group of a binary $q$-analog of the Fano
plane is either trivial or of order $2$.


title: Poisson cohomology of a class of log symplectic manifolds

abstract:
  We compute the Poisson cohomology of a class of Poisson manifolds that are
symplectic away from a collection $D$ of hypersurfaces. These Poisson
structures induce a generalization of symplectic and cosymplectic structures,
which we call a k-cosymplectic structure, on the intersection of hypersurfaces
in $D$.


title:
Edge States in the Climate System: Exploring Global Instabilities and
  Critical Transitions

abstract:
  Multistability is a ubiquitous feature in systems of geophysical relevance
and provides key challenges for our ability to predict a system's response to
perturbations. Near critical transitions small causes can lead to large effects
and - for all practical purposes - irreversible changes in the properties of
the system. The Earth climate is multistable: present astronomical and
astrophysical conditions support two stable regimes, the warm climate we live
in, and a snowball climate, characterized by global glaciation. We first
provide an overview of methods and ideas relevant for studying the climate
response to forcings and focus on the properties of critical transitions.
Following an idea developed by Eckhardt and co. for the investigation of
multistable turbulent flows, we study the global instability giving rise to the
snowball/warm multistability in the climate system by identifying the climatic
edge state, a saddle embedded in the boundary between the two basins of
attraction of the stable climates. The edge state attracts initial conditions
belonging to such a boundary and is the gate facilitating noise-induced
transitions between competing attractors. We use a simplified yet Earth-like
climate model constructed by coupling a primitive equations model of the
atmosphere with a simple diffusive ocean. We refer to the climatic edge states
as Melancholia states. We study their dynamics, their symmetry properties, and
we follow a complex set of bifurcations. We find situations where the
Melancholia state has chaotic dynamics. In these cases, the basin boundary
between the two basins of attraction is a strange geometric set with a nearly
zero codimension, and relate this feature to the time scale separation between
instabilities occurring on weather and climatic time scales. We also discover a
new stable climatic state characterized by non-trivial symmetry properties.

categories: physics.ao-ph cond-mat.stat-mech nlin.CD physics.comp-ph physics.flu-dyn


title:
Stretching and bending dynamics in triatomic ultralong-range Rydberg
  molecules

abstract:
  We investigate polyatomic ultralong-range Rydberg molecules consisting of
three ground state atoms bound to a Rydberg atom via $s$- and $p$-wave
interactions. By employing the finite basis set representation of the
unperturbed Rydberg electron Green's function we reduce the computational
effort to solve the electronic problem substantially. This method is
subsequently applied to determine the potential energy surfaces of triatomic
systems in electronic $s$- and $p$-Rydberg states. Their molecular geometry and
resulting vibrational structure are analyzed within an adiabatic approach that
separates the vibrational bending and stretching dynamics. This procedure
yields information on the radial and angular arrangement of the nuclei and
indicates in particular that kinetic couplings between bending and stretching
modes induce a linear structure in triatomic $l=0$ ultralong-range Rydberg
molecules.


title:
From the viscous Cahn-Hilliard equation to a regularized
  forward-backward parabolic equation

abstract:
  A rigorous proof is given for the convergence of the solutions of a viscous
Cahn-Hilliard system to the solution of the regularized version of the
forward-backward parabolic equation, as the coefficient of the diffusive term
goes to 0. Non-homogenous Neumann boundary condition are handled for the
chemical potential and the subdifferential of a possible non-smooth double-well
functional is considered in the equation. An error estimate for the difference
of solutions is also proved in a suitable norm and with a specified rate of
convergence.


title: The Frolicher-type inequalities of foliations

abstract:
  The purpose of this article is to adapt the Frolicher-type inequality to the
case of transversely holomorphic and transversely symplectic foliations. These
inequalities can be used to e.g. determine whether a given foliation can be
made transversely Kahler (due to their relations to various dd'-lemmas). Our
main results can be also stated for orbifolds as we point out in section 5 of
this paper.


title:
Phase coexistence and spatial correlations in reconstituting k-mer
  models

abstract:
  In reconstituting k-mer models, extended objects which occupy several sites
on a one dimensional lattice, undergo directed or undirected diffusion, and
reconstitute -when in contact- by transferring a single monomer unit from one
k-mer to the other; the rates depend on the size of participating k-mers. This
polydispersed system has two conserved quantities, the number of k-mers and the
packing fraction. We provide a matrix product method to write the steady state
of this model and to calculate the spatial correlation functions analytically.
We show that for a constant reconstitution rate, the spatial correlation
exhibits damped oscillations in some density regions separated, from other
regions with exponential decay, by a disorder surface. In a specific limit,
this constant-rate reconstitution model is equivalent to a single dimer model
and exhibits a phase coexistence similar to the one observed earlier in totally
asymmetric simple exclusion process on a ring with a defect.


title: A bottom-up approach to the strong CP problem

abstract:
  The strong CP problem is one of many puzzles in the theoretical description
of elementary particle physics that still lacks an explanation. While top-down
solutions to that problem usually comprise new symmetries or fields or both, we
want to present a rather bottom-up perspective. The main problem seems to be
how to achieve small CP violation in the strong interactions despite large CP
violation in weak interactions. Observation of CP violation is exclusively
through the Higgs--Yukawa interactions. In this paper, we show that with
minimal assumptions on the structure of mass (Yukawa) matrices they do not
contribute to the strong CP problem and thus we can provide a pathway to a
solution of the strong CP problem within the structures of the Standard Model
and no extension at the electroweak scale is needed. However, to address the
flavor puzzle, models based on minimal SU(3) flavor groups leading to the
proposed flavor matrices are favored. Though we refrain from an explicit a UV
completion of the Standard Model, we provide a simple requirement those models
should have to intrinsically not show a strong CP problem.


title: Approximating matrices and convex bodies through Kadison-Singer

abstract:
  We show that any $n\times m$ matrix $A$ can be approximated in operator norm
by a submatrix with a number of columns of order the stable rank of $A$. This
improves on existing results by removing an extra logarithmic factor in the
size of the extracted matrix. Our proof uses the recent solution of the
Kadison-Singer problem. We also develop a sort of tensorization technique to
deal with constraint approximation problems. As an application, we provide a
sparsification result with equal weights and an optimal approximate John's
decomposition for non-symmetric convex bodies. This enables us to show that any
convex body in $\mathbb{R}^n$ is arbitrary close to another one having $O(n)$
contact points and fills the gap left in the literature after the results of
Rudelson and Srivastava by completely answering the problem. As a consequence,
we also show that the method developed by Gu\'edon, Gordon and Meyer to
establish the isomorphic Dvoretzky theorem yields to the best known result once
we inject our improvements.


title:
Balitsky-Kovchegov equation at next-to-leading order accuracy with a
  resummation of large logarithms

abstract:
  We include resummation of large transverse logarithms into the
next-to-leading order Balitsky-Kovchegov equation. The resummed NLO evolution
equation is shown to be stable, the evolution speed being significantly reduced
by higher order corrections. The contributions from $\alpha_s^2$ terms that are
not enhanced by large logarithms are found to be numerically important close to
phenomenologically relevant initial conditions.


title: A dynamical presentation of the better than nice metric on the disc

abstract:
  This is a postprint of our paper "Force free Moebius motions of the circle"
(J. Geom. Symmetry Phys. 27 (2012) 59-65), which we hadn't uploaded to arXiv
previously. We would like to draw attention to the relationship with the
article "A geometry where everything is better than nice", by Larry Bates and
Peter Gibson (to appear in Proc. Amer. Math. Soc.). In our note we treat
thoroughly a simple particular case of two previous, more substantial articles.
We describe the force free Moebius motions of the circle, that is, the
geodesics of the Lie group M ~ PSL_2(R) ~ O_o(1,2) of Moebius transformations
of the circle, equipped with the Riemannian metric given by the kinetic energy
induced by the action. It turns up that M decomposes as a Riemannian product S
x D, where D is the unit disc endowed with a certain metric, which we now
recognize as being essentially the one that is better than nice. Concerning
geodesics, we only give the differential equation for their trajectories (using
Clairaut's Theorem); we took pleasure in learning from the article by Bates and
Gibson that they are actually hypocycloids.


title:
On the asymptotic stability of steady flows with nonzero flux in
  two-dimensional exterior domains

abstract:
  The Navier-Stokes equations in a two-dimensional exterior domain are
considered. The asymptotic stability of stationary solutions satisfying a
general hypothesis is proven under any $L^2$-perturbation. In particular the
general hypothesis is valid if the steady solution is the sum of the critically
decaying flux carrier with flux $|\Phi| < 2\pi$ and a small subcritically
decaying term. Under the central symmetry assumption, the general hypothesis is
also proven for any critically decaying steady solutions under a suitable
smallness condition.


title: A New Manifold Distance Measure for Visual Object Categorization

abstract:
  Manifold distances are very effective tools for visual object recognition.
However, most of the traditional manifold distances between images are based on
the pixel-level comparison and thus easily affected by image rotations and
translations. In this paper, we propose a new manifold distance to model the
dissimilarities between visual objects based on the Complex Wavelet Structural
Similarity (CW-SSIM) index. The proposed distance is more robust to rotations
and translations of images than the traditional manifold distance and the
CW-SSIM index based distance. In addition, the proposed distance is combined
with the $k$-medoids clustering method to derive a new clustering method for
visual object categorization. Experiments on Coil-20, Coil-100 and Olivetti
Face Databases show that the proposed distance measure is better for visual
object categorization than both the traditional manifold distances and the
CW-SSIM index based distances.


title: Stability Estimates for Truncated Fourier and Laplace Transforms

abstract:
  We prove sharp stability estimates for the Truncated Laplace Transform and
Truncated Fourier Transform. The argument combines an approach recently
introduced by Alaifari, Pierce and the second author for the truncated Hilbert
transform with classical results of Bertero, Gr\"unbaum, Landau, Pollak and
Slepian. In particular, we prove there is a universal constant $c >0$ such that
for all $f \in L^2(\mathbb{R})$ with compact support in $[-1,1]$ normalized to
$\|f\|_{L^2[-1,1]} = 1$ $$ \int_{-1}^{1}{|\widehat{f}(\xi)|^2d\xi} \gtrsim
\left(c\left\|f_x \right\|_{L^2[-1,1]} \right)^{- c\left\|f_x
\right\|_{L^2[-1,1]}}$$ The inequality is sharp in the sense that there is an
infinite sequence of orthonormal counterexamples if $c$ is chosen too small.
The question whether and to which extent similar inequalities hold for generic
families of integral operators remains open.


title:
On turbulence driven by axial precession and tidal evolution of the
  spin-orbit angle of close-in giant planets

abstract:
  The spin axis of a rotationally deformed planet is forced to precess about
its orbital angular momentum vector, due to the tidal gravity of its host star,
if these directions are misaligned. This induces internal fluid motions inside
the planet that are subject to a hydrodynamic instability. We study the
turbulent damping of precessional fluid motions, as a result of this
instability, in the simplest local computational model of a giant planet (or
star), with and without a weak internal magnetic field. Our aim is to determine
the outcome of this instability, and its importance in driving tidal evolution
of the spin-orbit angle in precessing planets (and stars). We find that this
instability produces turbulent dissipation that is sufficiently strong that it
could drive significant tidal evolution of the spin-orbit angle for hot
Jupiters with orbital periods shorter than about 10-18 days. If this mechanism
acts in isolation, this evolution would be towards alignment or anti-alignment,
depending on the initial angle, but the ultimate evolution (if other tidal
mechanisms also contribute) is expected to be towards alignment. The turbulent
dissipation is proportional to the cube of the precession frequency, so it
leads to much slower damping of stellar spin-orbit angles, implying that this
instability is unlikely to drive evolution of the spin-orbit angle in stars
(either in planetary or close binary systems). We also find that the
instability-driven flow can act as a system-scale dynamo, which may play a role
in producing magnetic fields in short-period planets.


title:
A Nonparametric Likelihood Approach for Inference in Instrumental
  Variable Models

abstract:
  Instrumental variable methods allow for inference about the treatment effect
by controlling for unmeasured confounding in randomized experiments with
noncompliance. However, many studies do not consider the observed compliance
behavior in the testing procedure, which can lead to a loss of power. In this
paper, we propose a novel nonparametric likelihood approach, referred to as the
binomial likelihood (BL) method, that incorporates information on compliance
behavior while overcoming several limitations of previous techniques and
utilizing the advantages of likelihood methods. Our proposed method produces
proper estimates of the counterfactual distribution functions by maximizing the
binomial likelihood over the space of distribution functions. Using this we
propose two versions of a binomial likelihood ratio test for the null
hypothesis of no treatment effect. We show that both versions are more powerful
to detect any distributional change than existing methods in finite sample
cases, and are asymptotically equivalent to the two-sample Anderson-Darling
test. We also develop an efficient algorithm for computing our estimates, and
apply the binomial likelihood method to a study of the effect of Medicaid
coverage on mental health using the Oregon Health Insurance Experiment.


title: Cold-atom Inertial Sensor without Deadtime

abstract:
  We report the operation of a cold-atom inertial sensor in a joint
interrogation scheme, where we simultaneously prepare a cold-atom source and
operate an atom interferometer in order to eliminate dead times. Noise aliasing
and dead times are consequences of the sequential operation which is intrinsic
to cold-atom atom interferometers. Both phenomena have deleterious effects on
the performance of these sensors. We show that our continuous operation
improves the short-term sensitivity of atom interferometers, by demonstrating a
record rotation sensitivity of $100$ nrad.s$^{-1}/\sqrt{\rm Hz}$ in a cold-atom
gyroscope of $11$ cm$^2$ Sagnac area. We also demonstrate a rotation stability
of $1$ nrad.s$^{-1}$ after $10^4$ s of integration, improving previous results
by an order of magnitude. We expect that the continuous operation will allow
cold-atom inertial sensors with long interrogation time to reach their full
sensitivity, determined by the quantum noise limit.


title:
Singular elliptic equation involving the GJMS operator on compact
  Riemannian manifold

abstract:
  In this paper we consider a singular elliptic equation involving the GJMS
(Graham-Jenne-Mason-Sparling) operator of order k on n-dimensional compact
Riemannian manifold with 2k<n. Mutiplicity and nonexistence results are
established.


title:
Adapting the Bron-Kerbosch Algorithm for Enumerating Maximal Cliques in
  Temporal Graphs

abstract:
  Dynamics of interactions play an increasingly important role in the analysis
of complex networks. A modeling framework to capture this are temporal graphs
which consist of a set of vertices (entities in the network) and a set of
time-stamped binary interactions between the vertices. We focus on enumerating
delta-cliques, an extension of the concept of cliques to temporal graphs: for a
given time period delta, a delta-clique in a temporal graph is a set of
vertices and a time interval such that all vertices interact with each other at
least after every delta time steps within the time interval. Viard, Latapy, and
Magnien [ASONAM 2015, TCS 2016] proposed a greedy algorithm for enumerating all
maximal delta-cliques in temporal graphs. In contrast to this approach, we
adapt the Bron-Kerbosch algorithm - an efficient, recursive backtracking
algorithm which enumerates all maximal cliques in static graphs - to the
temporal setting. We obtain encouraging results both in theory (concerning
worst-case running time analysis based on the parameter "delta-slice
degeneracy" of the underlying graph) as well as in practice with experiments on
real-world data. The latter culminates in an improvement for most interesting
delte-values concerning running time in comparison with the algorithm of Viard,
Latapy, and Magnien.


title:
Discovering Effect Modification in an Observational Study of Surgical
  Mortality at Hospitals with Superior Nursing

abstract:
  There is effect modification if the magnitude or stability of a treatment
effect varies systematically with the level of an observed covariate. A larger
or more stable treatment effect is typically less sensitive to bias from
unmeasured covariates, so it is important to recognize effect modification when
it is present. We illustrate a recent proposal for conducting a sensitivity
analysis that empirically discovers effect modification by exploratory methods,
but controls the family-wise error rate in discovered groups. The example
concerns a study of mortality and use of the intensive care unit in 23,715
matched pairs of two Medicare patients, one of whom underwent surgery at a
hospital identified for superior nursing, the other at a conventional hospital.
The pairs were matched exactly for 130 four-digit ICD-9 surgical procedure
codes and balanced 172 observed covariates. The pairs were then split into five
groups of pairs by CART in its effort to locate effect modification. The
evidence of a beneficial effect of magnet hospitals on mortality is least
sensitive to unmeasured biases in a large group of patients undergoing rather
serious surgical procedures, but in the absence of other life-threatening
conditions, such as a comorbidity of congestive heart failure or an emergency
admission leading to surgery.


title:
A rare example of low surface-brightness radio lobes in a gas-rich
  early-type galaxy: the story of NGC 3998

abstract:
  We study the nearby lenticular galaxy NGC 3998. This galaxy is known to host
a low-power radio AGN with a kpc-size one-sided jet and a large, nearly polar
HI disc. It is therefore a good system to study to understand the relation
between the availability of cold-gas and the triggering of AGNs in galaxies.
Our new WSRT data reveal two faint, S-shaped radio lobes extending out to
$\sim$10 kpc from the galaxy centre. Remarkably, we find that the inner HI disc
warps back towards the stellar mid-plane in a way that mirrors the warping of
the radio lobes. We suggest that the polar HI disc was accreted through a minor
merger, and that the torques causing it to warp in the inner regions are also
responsible for feeding the AGN. The "S" shape of the radio lobes would then be
due to the radio jets adapting to the changing angular momentum of the accreted
gas. The extended radio jets are likely poorly collimated, which would explain
their quick fading and, therefore, their rarity in galaxies similar to NGC
3998. The fuelling of the central super-massive black hole is likely occurring
via "discrete events", suggested by the observed variability of the radio core
and the extremely high core dominance, which we attribute to the formation and
ejection of a new jet resulting from a recent fuelling event.


title: Dimension of harmonic measures in hyperbolic spaces

abstract:
  We show exact dimensionality of harmonic measures associated with random
walks on groups acting on a hyperbolic space under finite first moment
condition, and establish the dimension formula by the entropy over the drift.
We also treat the case when a group acts on a non-proper hyperbolic space
acylindrically. Applications of this formula include continuity of the
Hausdorff dimension with respect to driving measures and Brownian motions on
regular coverings of a finite volume Riemannian manifold.


title:
Geometric Configuration of Riemannian Submanifolds of arbitrary
  Codimension

abstract:
  In this paper we study a geometric configuration of submanifolds of arbitrary
codimension in an ambient Riemannian space. We obtain relations between the
geometry of a q-codimension submanifold Mn along its boundary and the geometry
of the boundary of Mn as an hypersuface of a q-codimensional submanifold Pn in
an ambient space Mn+q. As a consequence of these geometric ralations we get
that the ellipticity of the generalized Newton transformations implies the
tranversality of Mn and Pn in Pn is totally geodesic in Mn+q.


title: Etale fundamental groups of affinoid $p$-adic curves

abstract:
  We prove that the geometric etale fundamental group of a (geometrically
connected) rigid smooth $p$-adic affinoid curve is a semi-direct factor of a
certain profinite free group. We also prove that the maximal pro-$p$ (resp.
maximal prime-to-$p$) quotient of this geometric \'etale fundamental group is
pro-$p$ free of infinite rank (resp. (pro-)prime-to-$p$ free of finite
computable rank).


title: Observation of photonic anomalous Floquet Topological Insulators

abstract:
  Commonly, a two-dimensional topological insulator is characterized by
non-zero Chern numbers associated with its band structure. In our work, we
present the experimental demonstration of an anomalous topological insulator,
for which the Chern numbers are always zero, and the winding number is the
appropriate quantity describing the topological character of the system. We
probe the robustness of the chiral edge states in such anomalous topological
insulators and analyze the phase transition between topological and trivial
phase.


title:
Optical to microwave clock frequency ratios with a nearly continuous
  strontium optical lattice clock

abstract:
  Optical lattice clocks are at the forefront of frequency metrology. Both the
instability and systematic uncertainty of these clocks have been reported to be
two orders of magnitude smaller than the best microwave clocks. For this
reason, a redefinition of the SI second based on optical clocks seems possible
in the near future. However, the operation of optical lattice clocks has not
yet reached the reliability that microwave clocks have achieved so far. In this
paper, we report on the operation of a strontium optical lattice clock that
spans several weeks, with more than 80% uptime. We make use of this long
integration time to demonstrate a reproducible measurement of frequency ratios
between the strontium clock transition and microwave Cs primary and Rb
secondary frequency standards.


title:
Holographic Shear Viscosity in Hyperscaling Violating Theories without
  Translational Invariance

abstract:
  In this paper we investigate the ratio of shear viscosity to entropy density,
$\eta/s$, in hyperscaling violating geometry with lattice structure. We show
that the scaling relation with hyperscaling violation gives a strong constraint
to the mass of graviton and usually leads to a power law of temperature,
$\eta/s\sim T^\kappa$. We find the exponent $\kappa$ can be greater than two
such that the new bound for viscosity raised in arXiv:1601.02757 is violated.
Our above observation is testified by constructing specific solutions with UV
completion in various holographic models. Finally, we compare the boundedness
of $\kappa$ with the behavior of entanglement entropy and conjecture a relation
between them.


title:
Fiat categorification of the symmetric inverse semigroup IS_n and the
  semigroup F^*_n

abstract:
  Starting from the symmetric group $S_n$, we construct two fiat
$2$-categories. One of them can be viewed as the fiat "extension" of the
natural $2$-category associated with the symmetric inverse semigroup
(considered as an ordered semigroup with respect to the natural order). This
$2$-category provides a fiat categorification for the integral semigroup
algebra of the symmetric inverse semigroup. The other $2$-category can be
viewed as the fiat "extension" of the $2$-category associated with the maximal
factorizable subsemigroup of the dual symmetric inverse semigroup (again,
considered as an ordered semigroup with respect to the natural order). This
$2$-category provides a fiat categorification for the integral semigroup
algebra of the maximal factorizable subsemigroup of the dual symmetric inverse
semigroup.


title: Numerical approximation of multi-phase Penrose-Fife systems

abstract:
  We consider a non-isothermal multi-phase field model. We subsequently
discretize implicitly in time and with linear finite elements. The arising
algebraic problem is formulated in two variables where one is the multi-phase
field, and the other contains the inverse temperature field. We solve this
saddle point problem numerically by a non-smooth Schur-Newton approach using
truncated non-smooth Newton multigrid methods. An application in grain growth
as occurring in liquid phase crystallization of silicon is considered.


title:
NuSTAR Hard X-ray Survey of the Galactic Center Region II: X-ray Point
  Sources

abstract:
  We present the first survey results of hard X-ray point sources in the
Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3-79 keV)
X-ray point sources in a 0.6 deg^2 region around Sgr A* with a total exposure
of 1.7 Ms, and 7 sources in the Sgr B2 field with 300 ks. We identify clear
Chandra counterparts for 58 NuSTAR sources and assign candidate counterparts
for the remaining 19. The NuSTAR survey reaches X-ray luminosities of ~4 x and
~8 x 10^32 erg s^-1 at the GC (8 kpc) in the 3-10 and 10-40 keV bands,
respectively. The source list includes three persistent luminous X-ray binaries
and the likely run-away pulsar called the Cannonball. New source-detection
significance maps reveal a cluster of hard (>10 keV) X-ray sources near the Sgr
A diffuse complex with no clear soft X-ray counterparts. The severe extinction
observed in the Chandra spectra indicates that all the NuSTAR sources are in
the central bulge or are of extragalactic origin. Spectral analysis of
relatively bright NuSTAR sources suggests that magnetic cataclysmic variables
constitute a large fraction (>40-60%). Both spectral analysis and logN-logS
distributions of the NuSTAR sources indicate that the X-ray spectra of the
NuSTAR sources should have kT > 20 keV on average for a single temperature
thermal plasma model or an average photon index of Gamma = 1.5 - 2 for a
power-law model. These findings suggest that the GC X-ray source population may
contain a larger fraction of X-ray binaries with high plasma temperatures than
the field population.


title:
Cross-Section Evidence-based Timelines for Software Process Improvement
  Retrospectives: A Case Study of User eXperience Integration

abstract:
  Although integrating UX practices into software development processes is a
type of Software Process Improvement (SPI) activity, this has not yet been
taken into account in UX publications. In this study, we approach UX
integration in a software development company in Sweden from a SPI perspective.
Following the guidelines in SPI literature, we performed a retrospective
meeting at the company to reflect on their decade of SPI activities for
enhancing UX integration. The aim of the meeting was to reflect on, learn from,
and coordinate various activities spanned across various organizational units
and projects. We therefore supported the meeting by a pre- generated timeline
of the main activities in the organization that is different from common
project retrospective meetings in SPI. This approach is a refinement of a
similar approach that is used in Agile projects, and is shown to improve
effectiveness of, and decrease memory bias. We hypothesized that this method
can be useful in the context of UX integration, and in this broader scope. To
evaluate the method we gathered practitioners' view through a questionnaire.
The findings showed our hypothesis to be plausible. Here, we present that UX
integration research and practice can benefit from the SPI body of knowledge;
We also show that such cross-section evidence-based timeline retrospective
meetings are useful for UX integration, and in a larger scale than one project,
especially for identifying and reflecting on 'organizational issues'. This
approach also provides a cross- section longitudinal overview of the SPI
activities that cannot easily be gained in other common SPI learning
approaches.


title: An Empirical-Bayes Score for Discrete Bayesian Networks

abstract:
  Bayesian network structure learning is often performed in a Bayesian setting,
by evaluating candidate structures using their posterior probabilities for a
given data set. Score-based algorithms then use those posterior probabilities
as an objective function and return the maximum a posteriori network as the
learned model. For discrete Bayesian networks, the canonical choice for a
posterior score is the Bayesian Dirichlet equivalent uniform (BDeu) marginal
likelihood with a uniform (U) graph prior (Heckerman et al., 1995). Its
favourable theoretical properties descend from assuming a uniform prior both on
the space of the network structures and on the space of the parameters of the
network. In this paper, we revisit the limitations of these assumptions; and we
introduce an alternative set of assumptions and the resulting score: the
Bayesian Dirichlet sparse (BDs) empirical Bayes marginal likelihood with a
marginal uniform (MU) graph prior. We evaluate its performance in an extensive
simulation study, showing that MU+BDs is more accurate than U+BDeu both in
learning the structure of the network and in predicting new observations, while
not being computationally more complex to estimate.


title:
Gone with the heat: A fundamental constraint on the imaging of dust and
  molecular gas in the early Universe

abstract:
  Images of dust continuum and carbon monoxide (CO) line emission are powerful
tools for deducing structural characteristics of galaxies, such as disk sizes,
H$_2$ gas velocity fields and enclosed H$_2$ and dynamical masses. We report on
a fundamental constraint set by the cosmic microwave background (CMB) on the
observed structural and dynamical characteristics of galaxies, as deduced from
dust continuum and CO-line imaging at high redshifts. As the CMB temperature
rises in the distant Universe, the ensuing thermal equilibrium between the CMB
and the cold dust and H$_2$ gas progressively erases all spatial and spectral
contrasts between their brightness distributions and the CMB. For high-redshift
galaxies, this strongly biases the recoverable H$_2$ gas and dust mass
distributions, scale lengths, gas velocity fields and dynamical mass estimates.
This limitation is unique to mm/submm wavelengths and unlike its known effect
on the global dust continuum and molecular line emission of galaxies, it cannot
be addressed simply. We nevertheless identify a unique signature of
CMB-affected continuum brightness distributions, namely an increasing rather
than diminishing contrast between such brightness distributions and the CMB
when the cold dust in distant galaxies is imaged at frequencies beyond the
Raleigh-Jeans limit. For the molecular gas tracers, the same effect makes the
atomic carbon (CI) lines maintain a larger contrast than the CO lines against
the CMB.


title:
Leading and next to leading large $n_f$ terms in the cusp anomalous
  dimension and the quark-antiquark potential

abstract:
  I discuss 3 related quantities: the cusp anomalous dimension, the HQET
heavy-quark field anomalous dimension, and the quark-antiquark potential.
Leading large $n_f$ terms can be calculated to all orders in $\alpha_s$. Next
to leading terms with the abelian color structure $C_F^2$ also can be found to
all orders (but not non-abelian $C_F C_A$ terms). This talk is based on
Appendices C and D in [arXiv:1510.07803].


title:
2D implementation of quantum annealing algorisms for fourth order binary
  optimization problems

abstract:
  Quantum annealing may provide advantages over simulated annealing on solving
some problems such as Kth order binary optimization problem. No feasible
architecture exists to implement the high-order optimization problem (K > 2) on
current quantum annealing hardware. We propose a two-dimensional quantum
annealing architecture to solve the 4th order binary optimization problem by
encoding four-qubit interactions within the coupled local fields acting on a
set of physical qubits. All possible four-body coupling terms for an N-qubit
system can be implemented through this architecture and are readily realizable
with the existing superconducting circuit technologies. The overhead of the
physical qubits is O(N4), which is the same as previously proposed
architectures in four-dimensional space. The equivalence between the
optimization problem Hamiltonian and the executable Hamiltonian is ensured by a
gauge invariant subspace of the experimental system. A scheme to realize local
gauge constraint by single ancillary qubit is proposed.


title: Constraining the Physical State by Symmetries

abstract:
  After reviewing the hole argument and its relations with initial value
problem and general covariance, we shall discuss how much freedom one has to
define the physical state of a system in a generally covariant (or gauge
covariant) field theory. We shall show that in gauge covariant theories (and
generally covariant theories with a a compact space) one has no freedom and one
is forced to declare as physically equivalent two configurations which differ
by a gauge transformation (or by a global spacetime diffeomorphism), as it is
usually prescribed. On the contrary, when space is not compact, the result
proven for the compact case does not hold true and one may have different
options to define physically equivalent configurations, still preserving
determinism.


title: Summary of the 2015 LHCb workshop on multi-body decays of D and B mesons

abstract:
  This document contains a summary of the LHCb workshop on multi-body decays of
D and B mesons, held at CBPF, Rio de Janeiro, in July 2015. The workshop was
focused on issues related to amplitude analysis of three- and four-body
hadronic decays. In addition to selected LHCb results, contributions from guest
theorists are included.


title: Power dissipation in fractal AC circuits

abstract:
  We extend Feynman's analysis of an infinite ladder circuit to fractal
circuits, providing examples in which fractal circuits constructed with purely
imaginary impedances can have characteristic impedances with positive real
part. Using (weak) self-similarity of our fractal structures, we provide
algorithms for studying the equilibrium distribution of energy on these
circuits. This extends the analysis of self-similar resistance networks
introduced by Fukushima, Kigami, Kusuoka, and more recently studied by
Strichartz et al.


title:
Poinca\'e type inequalities for vector functions with zero mean normal
  traces on the boundary and applications to interpolation methods

abstract:
  In the paper, we consider inequalities of the Poincar\'e--Steklov type for
subspaces of $H^1$-functions defined in a bounded domain $\Omega\in \Rd$ with
Lipschitz boundary $\partial\Omega$. For scalar valued functions, the subspaces
are defined by zero mean condition on $\partial\Omega$ or on a part of
$\partial\Omega$ having positive $d-1$ measure. For vector valued functions,
zero mean conditions are imposed on components (e.g., normal components) of the
function on certain $d-1$ dimensional manifolds (e.g., on plane or curvilinear
faces of $\partial\Omega$).
  We find explicit and simply computable bounds of the respective constants for
domains typically used in finite element methods (triangles, quadrilaterals,
tetrahedrons, prisms, pyramids, and domains composed of them). The second part
of the paper discusses applications of the estimates to interpolation of scalar
and vector valued functions. %383838


title: Local Distributed Verification

abstract:
  In the framework of distributed network computing, it is known that, for
every network predicate, each network configuration that satisfies this
predicate can be proved using distributed certificates which can be verified
locally. However, this requires to leak information about the identities of the
nodes in the certificates, which might not be applicable in a context in which
privacy is desirable. Unfortunately, it is known that if one insists on
certificates independent of the node identities, then not all network
predicates can be proved using distributed certificates that can be verified
locally. In this paper, we prove that, for every network predicate, there is a
distributed protocol satisfying the following two properties: (1) for every
network configuration that is legal w.r.t. the predicate, and for any attempt
by an adversary to prove the illegality of that configuration using distributed
certificates, there is a locally verifiable proof that the adversary is wrong,
also using distributed certificates; (2) for every network configuration that
is illegal w.r.t. the predicate, there is a proof of that illegality, using
distributed certificates, such that no matter the way an adversary assigns its
own set of distributed certificates in an attempt to prove the legality of the
configuration, the actual illegality of the configuration will be locally
detected. In both cases, the certificates are independent of the identities of
the nodes. These results are achieved by investigating the so-called local
hierarchy of complexity classes in which the certificates do not exploit the
node identities. Indeed, we give a characterization of such a hierarchy, which
is of its own interest


title:
Solutions to the Einstein-scalar-field system in spherical symmetry with
  large bounded variation norms

abstract:
  It is well-known that small, regular, spherically symmetric characteristic
initial data to the Einstein-scalar-field system which are decaying towards
(future null) infinity give rise to solutions which are foward-in-time global
(in the sense of future causal geodesic completeness). We construct a class of
spherically symmetric solutions which are global but the initial norms are
consistent with initial data not decaying towards infinity. This gives the
following consequences: (1) We prove that there exist foward-in-time global
solutions with arbitrarily large (and in fact infinite) initial bounded
variation (BV) norms and initial Bondi masses. (2) While general solutions with
non-decaying data do not approach Minkowski spacetime, we show using the
results of Luk--Oh that if a sufficiently strong asymptotic flatness condition
is imposed on the initial data, then the solutions we construct (with large BV
norms) approach Minkowski spacetime with a sharp inverse polynomial rate. (3)
Our construction can be easily extended so that data are posed at past null
infinity and we obtain solutions with large BV norms which are causally
geodesically complete both to the past and to the future. Finally, we discuss
applications of our method to construct global solutions for other nonlinear
wave equations with infinite critical norms.


title: On the large deviations of traces of random matrices

abstract:
  We present large deviations principles for the moments of the empirical
spectral measure of Wigner matrices and empirical measure of $\beta$-ensembles
in three cases : the case of Wigner matrices without Gaussian tails, that is
Wigner matrices whose entries have tail distributions decreasing as
$e^{-ct^{\alpha}}$, for some constant $c>0$ and with $\alpha \in (0,2)$, the
case of Gaussian Wigner matrices, and the case of $\beta$-ensembles associated
with a convex potential with polynomial growth.


title:
Pulse Shaping Diversity to Enhance Throughput in Ultra-Dense Small Cell
  Networks

abstract:
  Spatial multiplexing (SM) gains in multiple input multiple output (MIMO)
cellular networks are limited when used in combination with ultra-dense small
cell networks. This limitation is due to large spatial correlation among
channel pairs. More specifically, it is due to i) line-of-sight (LOS)
communication between user equipment (UE) and base station (BS) and ii)
in-sufficient spacing between antenna elements. We propose to shape transmit
signals at adjacent antennas with distinct interpolating filters which
introduces pulse shaping diversity eventually leading to improved SINR and
throughput at the UEs. In this technique, each antenna transmits its own data
stream with a relative offset with respect to adjacent antenna. The delay which
must be a fraction of symbol period is interpolated with the pulse shaped
signal and generates a virtual MIMO channel that leads to improved diversity
and SINR at the receiver. Note that non-integral sampling periods with
inter-symbol interference (ISI) should be mitigated at the receiver. For this,
we propose to use a fractionally spaced equalizer (FSE) designed based on the
minimum mean squared error (MMSE) criterion. Simulation results show that for a
2x2 MIMO and with inter-site-distance (ISD) of 50 m, the median received SINR
and throughput at the UE improves by a factor of 11 dB and 2x, respectively,
which verifies that pulse shaping can overcome poor SM gains in ultra-dense
small cell networks.


title: Characterization of the Riesz Exponential Family on homogeneous cones

abstract:
  In the paper we present a characterization theorem of the Riesz measure and a
Wishart exponential family on homogeneous cones through the invariance property
of a natural exponential family under the action of the triangular group.


title:
Fuel cell electrodes from organometallic Pt precursors: an easy
  atmospheric plasma approach

abstract:
  An organometallic powder (platinum (II) acetylacetonate) is decomposed in the
post-discharge of an atmospheric RF plasma torch to deposit Pt nanoparticles on
carbon black supports. The resulting nanohybrid materials are characterized by
FEG-SEM and XPS techniques to highlight their high content in Pt, their
oxidation degree, and the dispersion of the Pt nanoparticles on the substrate.
ICP-MS and electrochemical characterizations in a single fuel cell (cyclic
voltammetry, dynamic polarization curves) are also performed on electrodes
realized by treating the powder mixture overlaid on gas diffusion layers. The
comparison of the catalytic activity and the Pt loading with commercially
available electrodes shows the great potential of this simple innovative, fast,
and robust deposition method.


title:
Description of light nuclei in pionless effective field theory using the
  stochastic variational method

abstract:
  We construct a coordinate-space potential based on pionless effective field
theory with a Gaussian regulator. Charge-symmetry breaking is included through
the Coulomb potential and through two- and three-body contact interactions.
Starting with the effective field theory potential, we apply the stochastic
variational method to determine the ground states of nuclei with mass number
$A\leq 4$. At next-to-next-to-leading order, two out of three independent
three-body parameters can be fitted to the three-body binding energies. To fix
the remaining one, we look for a simultaneous description of the binding energy
of $^4$He and the charge radii of $^3$He and $^4$He. We show that at the order
considered we can find an acceptable solution, within the uncertainty of the
expansion. We find that the EFT expansion shows good agreement with empirical
data within the estimated uncertainty, even for a system as dense as $^4$He.


title: Spin-to-orbital angular momentum conversion in dielectric metasurfaces

abstract:
  Spin-to-orbital-angular-momentum conversion has attracted considerable
interest as a tool to create exotic light beams, leading to the emergence of
novel devices that implement this function. These converters exploit the
geometrical phase to create helical beams of handedness determined by the
chirality of the incident light. This property is finding important
applications in quantum optics thanks to the demonstration of liquid crystal
spin-to-orbital angular momentum converters (SOC) known as q-plates. Here we
demonstrate high-efficiency SOCs in the visible based on dielectric
metasurfaces that generate vortex beams with high and even fractional
topological charge and show for the first time the simultaneous generation of
collinear helical beams with different and arbitrary orbital angular momentum.
We foresee that this versatile method of creating vortex beams, which
circumvents the limitations of q-plates, will significant impact microscopy and
vector beam shaping.


title:
Numerical semigroups in a problem about economic incentives for
  consumers

abstract:
  Motivated by a promotion to increase the number of musical downloads, we
introduce the concept of $C$-incentive and show an algorithm that compute the
smallest $C$-incentive containing a subset $X \subseteq {\mathbb N}$. On the
other hand, in order to study $C$-incentives, we see that we can focus on
numerical $C$-incentives. Then, we establish that the set formed by all
numerical $C$-incentives is a Frobenius pseudo-variety and we show an
algorithmic process to recurrently build such a pseudo-variety.


title:
Analysis of a stochastic model for bacterial growth and the lognormality
  of the cell-size distribution

abstract:
  This paper theoretically analyzes a phenomenological stochastic model for
bacterial growth. This model comprises cell division and the linear growth of
cells, where growth rates and cell cycles are drawn from lognormal
distributions. We find that the cell size is expressed as a sum of independent
lognormal variables. We show numerically that the quality of the lognormal
approximation greatly depends on the distributions of the growth rate and cell
cycle. Furthermore, we show that actual parameters of the growth rate and cell
cycle take values that give a good lognormal approximation; thus, the
experimental cell-size distribution is in good agreement with a lognormal
distribution.


title:
Probing the noncommutative effects of phase space in the time-dependent
  Aharonov-Bohm effect

abstract:
  We study the noncommutative corrections on the time-dependent Aharonov-Bohm
effect when both the coordinate-coordinate and momentum-momentum
noncommutativities are considered. This study is motivated by the recent
observation that there is no net phase shift in the time-dependent AB effect on
the ordinary space, and therefore tiny derivation from zero can indicate new
physics. The vanishing of the time-dependent AB phase shift on the ordinary
space is preserved by the gauge and Lorentz symmetries. However, on the
noncomutative phase space, while the ordinary gauge symmetry can be kept by the
Seiberg-Witten map, but the Lorentz symmetry is broken. Therefore nontrivial
noncommutative corrections are expected. We find there are three kinds of
noncommutative corrections in general: 1) $\xi$-dependent correction which
comes from the noncommutativity among momentum operators; 2) momentum-dependent
correction which is rooted in the nonlocal interactions in the noncommutative
extended model; 3) momentum-independent correction which emerges become of the
gauge invariant condition on the nonlocal interactions in the noncommutative
model. We proposed two dimensionless quantities, which are based on the
distributions of the measured phase shift with respect to the external magnetic
field and to the cross section enclosed by the particle trajectory, to extract
the noncommutative parameters. We find that stronger (weaker) magnetic field
strength can give better bounds on the coordinate-coordinate
(momentum-momentum) noncommutative parameter, and large parameter space region
can be explored by the time-dependent AB effect.


title:
Van der Waals Stacking Induced Topological Phase Transition in Layered
  Ternary Transition Metal Chalcogenides

abstract:
  Novel materials with nontrivial electronic and photonic band topology are
crucial for realizing novel devices with low power consumption and heat
dissipation, and quantum computing free of decoherence. Here using
first-principles approach, we predict a class of ternary transition metal
chalcogenides (TTMC) MM'Te$_4$ exhibits dual topological characteristics:
quantum spin Hall (QSH) insulators in their 2D monolayers and topological Weyl
semimetals in their 3D noncentrosymmetric crystals upon van der Waals (vdW)
stacking. Remarkably, we find that one can create and annihilate Weyl fermions,
and realize the transition between Type-I and Type-II Weyl fermions by tuning
vdW interlayer spacing. Our calculations show that they possess excellent
thermodynamic stability and weak interlayer binding, implying their great
potentials for experimental synthesis, direct exfoliation and vdW
heterostacking. Moreover, their ternary nature will offer more tunability for
electronic structure by controlling different stoichiometry and valence
charges. Our findings provide an ideal materials platform for realizing QSH
effect and exploring topological phase transition, and will open up a variety
of new opportunities for two-dimensional materials and topological materials
research.


title: Towards a fully size-consistent method of increments

abstract:
  The method of increments (MoI) allows one to successfully calculate cohesive
energies of bulk materials with high accuracy, but it encounters difficulties
when calculating whole dissociation curves. The reason is that its standard
formalism is based on a single Hartree-Fock (HF) configuration whose orbitals
are localized and used for the many-body expansion. Therefore, in those
situations where HF does not allow a size-consistent description of the
dissociation, the MoI cannot yield proper results either. Herein we address the
problem by employing a size-consistent multiconfigurational reference for the
MoI formalism. This leads to a matrix equation where a coupling derived by the
reference itself is employed. In principle, such approach allows one to
evaluate approximate values for the ground as well as excited states energies.
While the latter are accurate close to the avoided crossing only, the ground
state results are very promising for the whole dissociation curve, as shown by
the comparison with density matrix renormalization group (DMRG) benchmarks. We
tested this two-state constant-coupling (TSCC)-MoI on beryllium rings of
different sizes and studied the error introduced by the constant coupling.


title: Thin times and random times' decomposition

abstract:
  The paper studies thin times which are random times whose graph is contained
in a countable union of the graphs of stopping times with respect to a
reference filtration $\mathbb F$. We show that a generic random time can be
decomposed into thin and thick parts, where the second is a random time
avoiding all $\mathbb F$-stopping times. Then, for a given random time $\tau$,
we introduce ${\mathbb F}^\tau$, the smallest right-continuous filtration
containing $\mathbb F$ and making $\tau$ a stopping time, and we show that, for
a thin time $\tau$, each $\mathbb F$-martingale is an ${\mathbb
F}^\tau$-semimartingale, i.e., the hypothesis $({\mathcal H}^\prime)$ for
$(\mathbb F, {\mathbb F}^\tau)$ holds. We present applications to honest times,
which can be seen as last passage times, showing classes of filtrations which
can only support thin honest times, or can accommodate thick honest times as
well.


title: Classical and Quantum Nonlocal Supergravity

abstract:
  We derive the N=1 supersymmetric extension for a class of weakly nonlocal
four dimensional gravitational theories.The construction is explicitly done in
the superspace and the tree-level perturbative unitarity is explicitly proved
both in the superfield formalism and in field components. For the minimal
nonlocal supergravity the spectrum is the same as in the local theory and in
particular it is ghost-free. The supersymmetric extension of the
super-renormalizable Starobinsky theory and of two alternative massive nonlocal
supergravities are found as straightforward applications of the formalism.
Power-counting arguments ensure super-renormalizability with milder requirement
for the asymptotic behavior of form factors than in ordinary nonlocal gravity.
The most noteworthy result, common to ordinary supergravity, is the absence of
quantum corrections to the cosmological constant in any regularization
procedure. We cannot exclude the usual one-loop quadratic divergences. However,
local vertices in the superfields, not undergoing renormalization, can be
introduced to cancel out such divergences. Therefore, quantum finiteness is
certainly achieved in dimensional regularization and most likely also in the
cut-off regularization scheme. We also discuss the n-point scattering
amplitudes making use of a general field redefinition theorem implemented in
the superspace. Finally, we show that all the exact solutions of the local
supergravity in vacuum are solutions of the nonlocal one too. In particular, we
have the usual Schwarzschild singularity. We infer that the weak nonlocality,
even in the presence of minimal supersymmetry, is not sufficient to solve the
spacetime singularities issue, although the theory is finite at quantum level.


title: A combinatorial problem and numerical semigroups

abstract:
  Let $a=(a_1,\ldots,a_n)$ and $b=(b_1,\ldots,b_n)$ be two $n$-tuples of
positive integers, let $X$ be a set of positive integers, and let $g$ be a
positive integer. In this work we show an algorithmic process in order to
compute all the sets $C$ of positive integers that fulfill the following
conditions: 1) the cardinality of $C$ is equal to $g$; 2) if $x,y\in \mathbb{N}
\setminus \{0\}$ and $x+y\in C$, then $C \cap \{x,y\} \neq \emptyset$; 3) if $x
\in C$ and $\frac{x-b_i}{a_i} \in \mathbb{N} \setminus \{0\}$ for some $i\in
\{1,\ldots,n\}$, then $\frac{x-b_i}{a_i} \in C$; 4) $X \cap C = \emptyset$.


title:
Approximations to the solution of Cauchy problem for a linear evolution
  equation via the space shift operator (second-order equation example)

abstract:
  We present a general method of solving the Cauchy problem for a linear
parabolic partial differential equation of evolution type with variable
coefficients and demonstrate it on the equation with derivatives of orders two,
one and zero. The method is based on the Chernoff approximation procedure
applied to a specially constructed shift operator. It is proven that
approximations converge uniformly to the exact solution.


title: Production and Decay of 750 Gev state of 6 top and 6 anti top quarks

abstract:
  Crude estimates are made of the branching ratios and pair production
cross-section for our previously proposed bound state S of six top and six
antitop quarks identified with the diphoton excess recently observed in ATLAS
and CMS. We estimate the pair production cross section to be approximately 12
times that for fourth family quarks. Hence we predict $\sigma(pp \rightarrow SS
+ anything) \approx 2$ pb at 13 TeV and an increase by a factor 10 over the
cross section at 8 TeV. Crude estimates of the main branching ratios relative
to the diphoton decay give $\Gamma(S\rightarrow \gamma+\gamma) \propto 1$,
$\Gamma(S\rightarrow t + \bar{t})\propto 378$, $\Gamma(S \rightarrow
gluon+gluon)\propto 117$, $\Gamma(S\rightarrow Higgs+Higgs)\propto 15$,
$\Gamma(S\rightarrow W+W)\propto 30$ and $\Gamma(S\rightarrow Z+Z) = 15$.
  These estimates are consistent with the LHC bounds at 8 TeV within a factor
1.25. We expect the $S \rightarrow \gamma\gamma$ events to be produced together
with another S resonance decaying typically into top-antitop or gluon-gluon
jets.


title:
An efficient Monte Carlo interior penalty discontinuous Galerkin method
  for elastic wave scattering in random media

abstract:
  This paper develops and analyzes an efficient Monte Carlo interior penalty
discontinuous Galerkin (MCIP-DG) method for elastic wave scattering in random
media. The method is constructed based on a multi-modes expansion of the
solution of the governing random partial differential equations. It is proved
that the mode functions satisfy a three-term recurrence system of partial
differential equations (PDEs) which are nearly deterministic in the sense that
the randomness only appears in the right-hand side source terms, not in the
coefficients of the PDEs. Moreover, the same differential operator applies to
all mode functions. A proven unconditionally stable and optimally convergent
IP-DG method is used to discretize the deterministic PDE operator, an efficient
numerical algorithm is proposed based on combining the Monte Carlo method and
the IP-DG method with the $LU$ direct linear solver. It is shown that the
algorithm converges optimally with respect to both the mesh size $h$ and the
sampling number $M$, and practically its total computational complexity is only
amount to solving very few deterministic elastic Helmholtz equations using the
$LU$ direct linear solver. Numerically experiments are also presented to
demonstrate the performance and key features of the proposed MCIP-DG method.


title:
Nearly Optimal Measurement Scheme in a Noisy Mach-Zehnder Interferometer
  with Coherent and Squeezed Vacuum

abstract:
  The use of an interferometer to perform an ultra-precise parameter estimation
under noisy conditions is a challenging task. Here we discuss nearly optimal
measurement schemes for a well known,sensitive input state, squeezed vacuum and
coherent light. We find that a single mode intensity measurement, while the
simplest and able to beat the shot-noise limit, is outperformed by other
measurement schemes in the low-power regime. However, at high powers, intensity
measurement is only outperformed by a small factor. Specifically, we confirm,
that an optimal measurement choice under lossless conditions is the parity
measurement. In addition, we also discuss the performance of several other
common measurement schemes when considering photon loss, detector efficiency,
phase drift, and thermal photon noise. We conclude that, with noise
considerations, homodyne remains near optimal in both the low and high power
regimes. Surprisingly, some of the remaining investigated measurement schemes,
including the previous optimal parity measurement, do not remain even near
optimal when noise is introduced.


title:
Local well-posedness for the Zakharov system on the background of a line
  soliton

abstract:
  We prove that the Cauchy problem for the two-dimensional Zakharov system is
locally well-posed for initial data which are localized perturbations of a line
solitary wave. Furthermore, for this Zakharov system, we prove weak convergence
to a nonlinear Schr\"odinger equation.


title:
NdCeCuO - NdCeO boundary and resistive switchings in mesoscopic
  structures on base of epitaxial NdCeCuO films

abstract:
  Reverse and stable bipolar resistive switching effect was observed in planar
NdCeCuO - NdCeO - Ag heterostructures. It was shown that the current voltage
charactereriscs of the BRSE observed has a diode character. Simulations were
used to consider the influence of the nonuniform distribution of an electric
field at the interface of a heterojunction on the effect of bipolar resistive
switching in investigated structures. The inhomogeneous distribution of the
electric field near the contact edge creates regions of higher electric field
strength which, in turn, stimulates motion and redistribution of defects,
changes of the resistive properties of the whole structure and formation of a
percolation channel.


title:
Dynamics of epidemic spreading with vaccination: impact of social
  pressure and engagement

abstract:
  In this work we consider a model of epidemic spreading coupled with an
opinion dynamics in a fully-connected population. Regarding the opinion
dynamics, the individuals may be in two distinct states, namely in favor or
against a vaccination campaign. Individuals against the vaccination follow a
standard SIS model, whereas the pro-vaccine individuals can also be in a third
compartment, namely Vaccinated. In addition, the opinions change according to
the majority-rule dynamics in groups with three individuals. We also consider
that the vaccine can give permanent or temporary immunization to the
individuals. By means of analytical calculations and computer simulations, we
show that the opinion dynamics can drastically affect the disease propagation,
and that the engagement of the pro-vaccine individuals can be crucial for
stopping the epidemic spreading. The full numerical code for simulate the model
is available from the authors' webpage.


title:
Optimizing human-interpretable dialog management policy using Genetic
  Algorithm

abstract:
  Automatic optimization of spoken dialog management policies that are robust
to environmental noise has long been the goal for both academia and industry.
Approaches based on reinforcement learning have been proved to be effective.
However, the numerical representation of dialog policy is
human-incomprehensible and difficult for dialog system designers to verify or
modify, which limits its practical application. In this paper we propose a
novel framework for optimizing dialog policies specified in domain language
using genetic algorithm. The human-interpretable representation of policy makes
the method suitable for practical employment. We present learning algorithms
using user simulation and real human-machine dialogs respectively.Empirical
experimental results are given to show the effectiveness of the proposed
approach.


title:
Optimal inference strategies and their implications for the linear noise
  approximation

abstract:
  We study the information loss of a class of inference strategies that is
solely based on time averaging. For an array of independent binary sensors
(e.g., receptors, single electron transistors) measuring a weak random signal
(e.g., ligand concentration, gate voltage) this information loss is up to 0.5
bit per measurement irrespective of the number of sensors. We derive a
condition related to the local detailed balance relation that determines
whether or not such a loss of information occurs. Specifically, if the free
energy difference arising from the signal is symmetrically distributed among
the forward and backward rates, time integration mechanisms will capture the
full information about the signal. As an implication, for the linear noise
approximation, we can identify the same loss of information, arising from its
inherent simplification of the dynamics.


title: Supernova Driving. III. Synthetic Molecular Cloud Observations

abstract:
  We present a comparison of molecular clouds (MCs) from a simulation of
supernova-driven interstellar medium (ISM) turbulence with real MCs from the
Outer Galaxy Survey. The radiative transfer calculations to compute synthetic
CO spectra are carried out assuming the CO relative abundance depends only on
gas density, according to four different models. Synthetic MCs are selected
above a threshold brightness temperature value, $T_{\rm B,min}=1.4$ K, of the
$J=1-0$ $^{12}$CO line, generating 16 synthetic catalogs (four different
spatial resolutions and four CO abundance models), each containing up to
several thousands MCs. The comparison with the observations focuses on the mass
and size distributions and on the velocity-size and mass-size Larson relations.
The mass and size distributions are found to be consistent with the
observations, with no significant variations with spatial resolution or
chemical model, except in the case of the unrealistic model with constant CO
abundance. The velocity-size relation is slightly too steep for some of the
models, while the mass-size relation is a bit too shallow for all models only
at a spatial resolution $dx\approx 1$ pc. The normalizations of the Larson
relations show a clear dependence on spatial resolution, for both the synthetic
and the real MCs. The comparison of the velocity-size normalization suggests
that the SN rate in the Perseus arm is approximately 70\% or less of the rate
adopted in the simulation. Overall, the realistic properties of the synthetic
clouds confirm that supernova-driven turbulence can explain the origin and
dynamics of MCs.


title: Additive functionals of $d$-ary increasing trees

abstract:
  A tree functional is called additive if it satisfies a recursion of the form
$F(T) = \sum_{j=1}^k F(B_j) + f(T)$, where $B_1,\ldots,B_k$ are the branches of
the tree $T$ and $f(T)$ is a toll function. We prove a general central limit
theorem for additive functionals of $d$-ary increasing trees under suitable
assumptions on the toll function. The same method also applies to generalised
plane-oriented increasing trees (GPORTs). One of our main applications is a
log-normal law that we prove for the size of the automorphism group of $d$-ary
increasing trees, but many other examples (old and new) are covered as well.


title:
Autocatalytic sets in polymer networks with variable catalysis
  distributions

abstract:
  All living systems -- from the origin of life to modern cells -- rely on a
set of biochemical reactions that are simultaneously self-sustaining and
autocatalytic. This notion of an autocatalytic set has been formalized
graph-theoretically (as `RAF'), leading to mathematical results and
polynomial-time algorithms that have been applied to simulated and real
chemical reaction systems. In this paper, we investigate the emergence of
autocatalytic sets in polymer models when the catalysis rate of each molecule
type is drawn from some probability distribution. We show that although the
average catalysis rate $f$ for RAFs to arise depends on this distribution, a
universal linear upper and lower bound for $f$ (with increasing system size)
still applies. However, the probability of the appearance (and size) of
autocatalytic sets can vary widely, depending on the particular catalysis
distribution. We use simulations to explore how tight the mathematical bounds
are, and the reasons for the observed variations. We also investigate the
impact of inhibition (where molecules can also inhibit reactions) on the
emergence of autocatalytic sets, deriving new mathematical and algorithmic
results.


title: On Elliptic String Solutions in AdS(3) and dS(3)

abstract:
  Classical string actions in AdS(3) and dS(3) can be connected to the
sinh-Gordon and cosh-Gordon equations through Pohlmeyer reduction. We show that
the problem of constructing a classical string solution with a given static or
translationally invariant Pohlmeyer counterpart is equivalent to solving four
pairs of effective Schrodinger problems. Each pair consists of a flat potential
and an n = 1 Lame potential whose eigenvalues are connected, and, additionally,
the four solutions satisfy a set of constraints. An approach for solving this
system is developed by employing an interesting connection between the specific
class of classical string solutions and the band structure of the Lame
potential. This method is used for the construction of several families of
classical string solutions, one of which turns out to be the spiky strings in
AdS(3). New solutions include circular rotating strings in AdS(3) with singular
time evolution of their radius and angular velocity as well as classical string
solutions in dS(3).


title: Intertwined Lattice Deformation and Magnetism in Monovacancy Graphene

abstract:
  Using density functional calculations we have investigated the local spin
moment formation and lattice deformation in graphene when an isolated vacancy
is created. We predict two competing equilibrium structures: a ground state
planar configuration with a saturated local moment of 1.5 $\mu_B$, and a
metastable non-planar configuration with a vanishing magnetic moment, at a
modest energy expense of ~50 meV. Though non-planarity relieves the lattice of
vacancy-induced strain, the planar state is energetically favored due to
maximally localized defect states (v$\sigma$, v$\pi$). In the planar
configuration, charge transfer from itinerant (Dirac) states weakens the
spin-polarization of v$\pi$ yielding a fractional moment, which is aligned
parallel to the unpaired v$\sigma$ electron through Hund's coupling. In the
non-planar configuration, the absence of orthogonal symmetry allows interaction
between v$\sigma$ and local d$\pi$ states, to form a hybridized
v$\sigma^\prime$ state. The non-orthogonality also destabilizes the Hund's
coupling, and an antiparallel alignment between v$\sigma$ and v$\pi$ lowers the
energy. The gradual spin reversal of v$\pi$ with increasing non-planarity opens
up the possibility of an intermediate structure with balanced v$\pi$ spin
population. If such a structure is realized under external perturbations,
diluted vacancy concentration may lead to v$\sigma$ based spin-1/2
paramagnetism.


title:
Spectral properties of large gradual solar energetic particle events -
  II -Systematic Q/M-dependence of heavy ion spectral breaks

abstract:
  We fit the $\sim$0.1-500 MeV/nucleon H-Fe spectra in 46 large SEP events
surveyed by Desai et al. (2016) with the double power-law Band function to
obtain a normalization constant, low- and high-energy parameters $\gamma_a$ and
$\gamma_b$; and break energy $E_B$. We also calculate the low-energy power-law
spectral slope $\gamma_1$. We find that: 1) $\gamma_a$, $\gamma_1$, and
$\gamma_b$ are species-independent within a given SEP event, and the spectra
steepen with increasing energy; 2) $E_B$'s are well ordered by Q/M ratio, and
decrease systematically with decreasing Q/M, scaling as (Q/M)$^\alpha$ with
$\alpha$ varying between $\sim$0.2-3; 3) $\alpha$ is well correlated with Fe/O
at $\sim$0.16-0.23 MeV/nucleon and CME speed; 4) In most events: $\alpha<$1.4,
the spectra steepen significantly at higher energy with $\gamma_b$-$\gamma_a
>$3; and 5) Seven out of 9 extreme SEP events (associated with faster CMEs and
GLEs) are Fe-rich, have $\alpha >$1.4, have flatter spectra at low and high
energies with $\gamma_b$-$\gamma_a <$3. The species-independence of $\gamma_a$,
$\gamma_1$, and $\gamma_b$ and the systematic Q/M dependence of $E_B$ within an
event, as well as the range of values for $\alpha$ suggest that the formation
of double power-laws in SEP events occurs primarily due to diffusive
acceleration at near-Sun CME shocks and not due to scattering in the
interplanetary turbulence. In most events, the Q/M-dependence of $E_B$ is
consistent with the equal diffusion coefficient condition while the
event-to-event variations in $\alpha$ are probably driven by differences in the
near-shock wave intensity spectra, which are flatter than the Kolmogorov
turbulence spectrum but still weaker compared to that inferred for the extreme
events.


title: Manipulation of optical-pulse-imprinted memory in a $\Lambda$ system

abstract:
  We examine coherent memory manipulation in a $\Lambda$-type medium, using the
second order solution presented by Groves, Clader and Eberly [J. Phys. B: At.
Mol. Opt. Phys. 46, 224005 (2013)] as a guide. The analytical solution obtained
using the Darboux transformation and a nonlinear superposition principle
describes complicated soliton-pulse dynamics which, by an appropriate choice of
parameters, can be simplified to a well-defined sequence of pulses interacting
with the medium. In this report, this solution is reviewed and put to test by
means of a series of numerical simulations, encompassing all the parameter
space and adding the effects of homogeneous broadening due to spontaneous
emission. We find that even though the decohered results deviate from the
analytical prediction they do follow a similar trend that could be used as a
guide for future experiments.


title: Joint Embeddings of Hierarchical Categories and Entities

abstract:
  Due to the lack of structured knowledge applied in learning distributed
representation of categories, existing work cannot incorporate category
hierarchies into entity information.~We propose a framework that embeds
entities and categories into a semantic space by integrating structured
knowledge and taxonomy hierarchy from large knowledge bases. The framework
allows to compute meaningful semantic relatedness between entities and
categories.~Compared with the previous state of the art, our framework can
handle both single-word concepts and multiple-word concepts with superior
performance in concept categorization and semantic relatedness.


title:
Genuine T, CP, CPT asymmetry parameters for the entangled
  $\boldsymbol{B_d}$ system

abstract:
  The precise connection between the theoretical T, CP, CPT asymmetries, in
terms of transition probabilities between the filtered neutral meson $B_d$
states and the experimental asymmetries between the double decay rate
intensities for Flavour-CP eigenstate decay products in a B-factory of
entangled states, is established. This allows the identification of genuine
Asymmetry Parameters in the time distribution of the asymmetries and their
measurability by disentangling genuine and possible fake terms. We express the
nine asymmetry parameters -- three different observables for each one of the
three symmetries -- in terms of the ingredients of the Weisskopf-Wigner
dynamical description of the entangled $B_d$-meson states and we obtain a
global fit to their values from the BaBar collaboration experimental results.
The possible fake terms are all compatible with zero and the information
content of the nine asymmetry parameters is indeed different. The non-vanishing
$\Delta\mathscr S_c^{\rm T} =-0.687\pm 0.020 $ and $\Delta\mathscr S_c^{\rm
CP}=-0.680\pm 0.021$ are impressive separate direct evidence of
Time-Reversal-violation and CP-violation in these transitions and compatible
with Standard Model expectations. An intriguing 2$\sigma$ effect for the
Re($\theta$) parameter responsible of CPT-Violation appears which, interpreted
as an upper limit, leads to $|M_{\bar B^0\bar B^0}-M_{B^0B^0}| < 4.0\times
10^{-5}$ eV at 95\% C.L. for the diagonal flavour terms of the mass matrix. It
contributes to the CP-violating $\Delta\mathscr C_c^{\rm CP}$ asymmetry
parameter in an unorthodox manner -- in its $\cos(\Delta M\,t)$ time dependence
--, and it is accessible in facilities with non-entangled $B_d$'s, like the
LHCb experiment.


title: A Rate-Splitting Strategy for Max-Min Fair Multigroup Multicasting

abstract:
  We consider the problem of transmit beamforming to multiple cochannel
multicast groups. The conventional approach is to beamform a designated data
stream to each group, while treating potential inter-group interference as
noise at the receivers. In overloaded systems where the number of transmit
antennas is insufficient to perform interference nulling, we show that
inter-group interference dominates at high SNRs, leading to a saturating
max-min fair performance. We propose a rather unconventional approach to cope
with this issue based on the concept of Rate-Splitting (RS). In particular,
part of the interference is broadcasted to all groups such that it is decoded
and canceled before the designated beams are decoded. We show that the RS
strategy achieves significant performance gains over the conventional
multigroup multicast beamforming strategy.


title:
A posteriori error estimators for stabilized finite element
  approximations of an optimal control problem

abstract:
  We derive a posteriori error estimators for an optimal control problem
governed by a convection-reaction-diffusion equation; control constraints are
also considered. We consider a family of low-order stabilized finite element
methods to approximate the solutions to the state and adjoint equations. We
obtain a fully computable a posteriori error estimator for the optimal control
problem. All the constants that appear in the upper bound for the error are
fully specified. Therefore, the proposed estimator can be used as a stopping
criterion in adaptive algorithms. We also obtain a robust a posteriori error
estimator for when the error is measured in a norm that involves the dual norm
of the convective derivative. Numerical examples, in two and three dimensions,
are presented to illustrate the theory.


title: Reionization and dark matter decay

abstract:
  Cosmic reionization and dark matter decay can impact observations of the
cosmic microwave sky in a similar way. A simultaneous study of both effects is
required to constrain unstable dark matter from cosmic microwave background
observations. We compare two reionization models with and without dark matter
decay. We find that a reionization model that fits also data from quasars and
star forming galaxies results in tighter constraints on the reionization
optical depth $\tau_{\text{reio}}$, but weaker constraints on the spectral
index $n_{\text{s}}$ than the conventional parametrization. We use the Planck
2015 data to constrain the effective decay rate of dark matter to $\Gamma_{\rm
eff} < 2.9 \times 10^{-25}/$s at $95$\% C.L. This limit is robust and model
independent. It holds for any type of decaying dark matter and it depends only
weakly on the chosen parametrization of astrophysical reionization. For light
dark matter particles that decay exclusively into electromagnetic components
this implies a limit of $\Gamma < 5.3 \times 10^{-26}/$s at $95$\% C.L.
Specifying the decay channels, we apply our result to the case of keV-mass
sterile neutrinos as dark matter candidates and obtain constraints on their
mixing angle and mass, which are comparable to the ones from the diffuse X-ray
background.


title: A note on the automorphism group of Schubert varieties

abstract:
  In this work we extend some previously known results on the automorphism
group of Schubert varieties. We consider the Schubert conditions which define a
Schubert variety. An automorphism of the Grassmannian fixes a Schubert variety
contained in it if and only if it fixes certain elements of the flag used to
define the Schubert conditions.


title:
An Alternative Framework for Time Series Decomposition and Forecasting
  and its Relevance for Portfolio Choice: A Comparative Study of the Indian
  Consumer Durable and Small Cap Sectors

abstract:
  One of the challenging research problems in the domain of time series
analysis and forecasting is making efficient and robust prediction of stock
market prices. With rapid development and evolution of sophisticated algorithms
and with the availability of extremely fast computing platforms, it has now
become possible to effectively extract, store, process and analyze high volume
stock market time series data. Complex algorithms for forecasting are now
available for speedy execution over parallel architecture leading to fairly
accurate results. In this paper, we have used time series data of the two
sectors of the Indian economy: Consumer Durables sector and the Small Cap
sector for the period January 2010 to December 2015 and proposed a
decomposition approach for better understanding of the behavior of each of the
time series. Our contention is that various sectors reveal different time
series patterns and understanding them is essential for portfolio formation.
Further, based on this structural analysis, we have also proposed several
robust forecasting techniques and analyzed their accuracy in prediction using
suitably chosen training and test data sets. Extensive results are presented to
demonstrate the effectiveness of our propositions.


title: Estimates on singular values of functions of perturbed operators

abstract:
  This is a conitunation of [1] and [2]. We prove that if function $f$ belongs
to the class $\Lambda_{\omega} \overset{\text{def}}{=} \{f:
\omega_{f}(\delta)\leq \text{const} \omega(\delta)\} $ for an arbitrary modulus
of continuity $\omega$, then $s_j(f(A)-f(B))\leq c\cdot
\omega_{\ast}\big((1+j)^{-\frac{1}{p}}\Vert A-B \Vert_{S_{p}^l}\big) \cdot
\Vert f \Vert_{\Lambda_{\omega}}$ for arbitrary self-adjoint operators $A$, $B$
and all $1\leq j\leq l$, where $\omega_{\ast}(x) \overset{\text{def}}{=} x
\int_{x}^{\infty}\frac{\omega(t)}{t^2}dt ( x>0) $. The result is then
generalized for contractions, maximal dissipative operators, normal operators
and $n$-tuples of commuting self-adjoint operators.


title: Secure and trusted white-box verification

abstract:
  Verification is the process of checking whether a product has been
implemented according to its prescribed specifications. We study the case of a
designer (the developer) that needs to verify its design by a third party (the
verifier), by making publicly available a limited amount of information about
the design, namely a diagram of interconnections between the different design
components, but not the components themselves or the intermediate values passed
between components. We formalize this notion of limited information using
tabular expressions as the description method for both the specifications and
the design. Treating verification as a process akin to testing, we develop
protocols that allow for the design to be verified on a set of inputs generated
by the verifier, using any test-case generating algorithm that can take
advantage of this extra available information (partially white-box testing),
and without compromising the developer's secret information. Our protocols work
with both trusted and untrusted developers, and allow for the checking of the
correctness of the verification process itself by any third party, and at any
time.


title: Competitive analysis of the top-K ranking problem

abstract:
  Motivated by applications in recommender systems, web search, social choice
and crowdsourcing, we consider the problem of identifying the set of top $K$
items from noisy pairwise comparisons. In our setting, we are non-actively
given $r$ pairwise comparisons between each pair of $n$ items, where each
comparison has noise constrained by a very general noise model called the
strong stochastic transitivity (SST) model. We analyze the competitive ratio of
algorithms for the top-$K$ problem. In particular, we present a linear time
algorithm for the top-$K$ problem which has a competitive ratio of
$\tilde{O}(\sqrt{n})$; i.e. to solve any instance of top-$K$, our algorithm
needs at most $\tilde{O}(\sqrt{n})$ times as many samples needed as the best
possible algorithm for that instance (in contrast, all previous known
algorithms for the top-$K$ problem have competitive ratios of
$\tilde{\Omega}(n)$ or worse). We further show that this is tight: any
algorithm for the top-$K$ problem has competitive ratio at least
$\tilde{\Omega}(\sqrt{n})$.


title: Contraadjusted modules, contramodules, and reduced cotorsion modules

abstract:
  This paper is devoted to the more elementary aspects of the contramodule
story, and can be viewed as an extended introduction to the more technically
complicated arXiv:1503.05523. Reduced cotorsion abelian groups form an abelian
category, which is in some sense covariantly dual to the category of torsion
abelian groups. An abelian group is reduced cotorsion if and only if it is
isomorphic to a product of p-contramodule abelian groups over prime numbers p.
Any p-contraadjusted abelian group is p-adically complete, and any p-adically
separated and complete group is a p-contramodule, but the converse assertions
are not true. In some form, these results hold for modules over arbitrary
commutative rings, while other formulations are applicable to modules over
one-dimensional Noetherian rings.


title: Long-time existence of the edge Yamabe flow

abstract:
  This article presents an analysis of the normalized Yamabe flow starting at
and preserving a class of compact Riemannian manifolds with incomplete edge
singularities and negative Yamabe invariant. Our main results include
uniqueness, long-time existence and convergence of the edge Yamabe flow
starting at a metric with everywhere negative scalar curvature. Our methods
include novel maximum principle results on the singular edge space without
using barrier functions. Moreover, our uniform bounds on solutions are
established by a new ansatz without in any way using or redeveloping
Krylov-Safonov estimates in the singular setting. As an application we obtain a
solution to the Yamabe problem for incomplete edge metrics with negative Yamabe
invariant using flow techniques. Our methods lay groundwork for studying other
flows like the mean curvature flow as well as the porous medium equation in the
singular setting.


title: Residual irreducibility of compatible systems

abstract:
  We show that if $\{\rho_{\ell}\}$ is a compatible system of absolutely
irreducible Galois representations of a number field then the residual
representation $\overline{\rho}_{\ell}$ is absolutely irreducible for $\ell$ in
a density 1 set of primes. The key technical result is the following theorem:
the image of $\rho_{\ell}$ is an open subgroup of a hyperspecial maximal
compact subgroup of its Zariski closure with bounded index (as $\ell$ varies).
This result combines a theorem of Larsen on the semi-simple part of the image
with an analogous result for the central torus that was recently proved by
Barnet-Lamb, Gee, Geraghty, and Taylor, and for which we give a new proof.


title: The star-formation rate density from z = 0-6

abstract:
  We use 3035 Herschel-SPIRE 500$\mu$m sources from 20.3 sq deg of sky in the
HerMES Lockman, ES1 and XMM-LSS areas to estimate the star-formation rate
density at z = 1-6. 500 mu sources are associated first with 350 and 250 mu
sources, and then with Spitzer 24 mu sources from the SWIRE photometric
redshift catalogue. The infrared and submillimetre data are fitted with a set
of radiative-transfer templates corresponding to cirrus (quiescent) and
starburst galaxies. Lensing candidates are removed via a set of colour-colour
and colour-redshift constraints. Star-formation rates are found to extend from
< 1 to 20,000 Mo/yr. Such high values were also seen in the all-sky IRAS Faint
Source Survey. Star-formation rate functions are derived in a series of
redshift bins from 0-6, combined with earlier far-infrared estimates, where
available, and fitted with a Saunders et al (1990) functional form. The
star-formation-rate density as a function of redshift is derived and compared
with other estimates. There is reasonable agreement with both infrared and
ultraviolet estimates for z < 3, but we find higher star-formation-rate
densities than ultraviolet estimates at z = 3-6. Given the considerable
uncertainties in the submillimetre estimates, we can not rule out the
possibility that the ultraviolet estimates are correct. But the possibility
that the ultraviolet estimates have seriously underestimated the contribution
of dust-shrouded star-formation can also not be excluded.


title: The Canarias Einstein Ring: a Newly Discovered Optical Einstein Ring

abstract:
  We report the discovery of an optical Einstein Ring in the Sculptor
constellation, IAC J010127-334319, in the vicinity of the Sculptor Dwarf
Spheroidal Galaxy. It is an almost complete ring ($\sim 300^{\circ}$) with a
diameter of $\sim 4.5\, {\rm arcsec}$. The discovery was made serendipitously
from inspecting Dark Energy Camera (DECam) archive imaging data. Confirmation
of the object nature has been obtained by deriving spectroscopic redshifts for
both components, lens and source, from observations at the $10.4$ m Gran
Telescopio CANARIAS (GTC) with the spectrograph OSIRIS. The lens, a massive
early-type galaxy, has a redshift of ${\rm z}=0.581$ while the source is a
starburst galaxy with redshift of ${\rm z}=1.165$. The total enclosed mass that
produces the lensing effect has been estimated to be ${\rm M_{tot}=(1.86 \pm
0.23) \,\cdot 10^{12}\, {\rm M_{\odot}}}$.


title: Heavy-ion physics at the LHC: Review of Run I results

abstract:
  In this work we review what we consider are, some of the most relevant
results of heavy-ion physics at the LHC. This paper is not intended to cover
all the many important results of the experiments, instead we present a brief
overview of the current status on the characterization of the hot and dense QCD
medium produced in the heavy-ion collisions. Recent exciting results which are
still under debate are discussed too, leading to intriguing questions like
whether we have a real or fake QGP formation in small systems.


title: The Nucleus of the Planetary Nebula EGB 6 as a Post-Mira Binary

abstract:
  EGB 6 is a faint, large, ancient planetary nebula (PN). Its central star, a
hot DAOZ white dwarf (WD), is a prototype of a rare class of PN nuclei
associated with dense, compact emission-line knots. The central star also shows
excess fluxes in both the near- (NIR) and mid-infrared (MIR). In a 2013 paper,
we used Hubble Space Telescope (HST) images to show that the compact nebula is
a point-like source, located 0".16 (~118 AU) from the WD. We attributed the NIR
excess to an M dwarf companion star, which appeared to coincide with the dense
emission knot. We now present new ground-based NIR spectroscopy, showing that
the companion is actually a much cooler source with a continuous spectrum,
apparently a dust-enshrouded low-luminosity star. New HST images confirm common
proper motion of the emission knot and red source with the WD. The I-band, NIR,
and MIR fluxes are variable, possibly on timescales as short as days. We can
fit the spectral-energy distribution with four blackbodies (the WD, a ~1850 K
NIR component, and MIR dust at 385 and 175 K). Alternatively, we show that the
NIR/MIR SED is very similar to that of Class 0/I young stellar objects. We
suggest a scenario in which the EGB 6 nucleus is descended from a wide binary
similar to the Mira system, in which a portion of the wind from an AGB star was
captured into an accretion disk around a companion star; a remnant of this disk
has survived to the present time, and is surrounded by gas photoionized by UV
radiation from the WD.


title: A Deep Search for Additional Satellites around the Dwarf Planet Haumea

abstract:
  Haumea is a dwarf planet with two known satellites, an unusually high spin
rate, and a large collisional family, making it one of the most interesting
objects in the outer solar system. A fully self-consistent formation scenario
responsible for the satellite and family formation is still elusive, but some
processes predict the initial formation of many small moons, similar to the
small moons recently discovered around Pluto. Deep searches for regular
satellites around KBOs are difficult due to observational limitations, but
Haumea is one of the few for which sufficient data exist. We analyze Hubble
Space Telescope (HST) observations, focusing on a ten-consecutive-orbit
sequence obtained in July 2010, to search for new very small satellites. To
maximize the search depth, we implement and validate a non-linear
shift-and-stack method. No additional satellites of Haumea are found, but by
implanting and recovering artificial sources, we characterize our sensitivity.
At distances between $\sim$10,000 km and $\sim$350,000 km from Haumea,
satellites with radii as small as $\sim$10 km are ruled out, assuming an albedo
($p \simeq 0.7$) similar to Haumea. We also rule out satellites larger than
$\gtrsim$40 km in most of the Hill sphere using other HST data. This search
method rules out objects similar in size to the small moons of Pluto. By
developing clear criteria for determining the number of non-linear rates to
use, we find that far fewer shift rates are required ($\sim$35) than might be
expected. The non-linear shift-and-stack method to discover satellites (and
other moving transients) is tractable, particularly in the regime where
non-linear motion begins to manifest itself.