title: A sparse multidimensional FFT for real positive vectors

abstract:
  We present a sparse multidimensional FFT (sMFFT) randomized algorithm for
real positive vectors. The algorithm works in any fixed dimension, requires
(O(R log(R) log(N)) ) samples and runs in O( R log^2(R) log(N)) complexity
(where N is the total size of the vector in d dimensions and R is the number of
nonzeros). It is stable to low-level noise and exhibits an exponentially small
probability of failure.


title:
Analytical recursive method to ascertain multisite entanglement in doped
  quantum spin ladders

abstract:
  We formulate an analytical recursive method to generate the wave function of
doped short-range resonating valence bond (RVB) states as a tool to efficiently
estimate multisite entanglement as well as other physical quantities in doped
quantum spin ladders. We prove that doped RVB ladder states are always genuine
multipartite entangled. Importantly, our results show that within specific
doping concentration and model parameter regimes, the doped RVB state
essentially characterizes the trends of genuine multiparty entanglement in the
exact ground states of the Hubbard model with large onsite interactions, in the
limit which yields the $t$-$J$ Hamiltonian.


title: Robust Zero-Field Skyrmion Formation in FeGe Epitaxial Thin Films

abstract:
  B20 phase magnetic materials, such as FeGe, have been of significant
interests in recent years because they enable magnetic skyrmions, which can
potentially lead to low energy cost spintronic applications. One major effort
in this emerging field is the stabilization of skyrmions at room temperature
and zero external magnetic field. We report the growth of phase-pure FeGe
epitaxial thin films on Si(111) substrates by ultrahigh vacuum off-axis
sputtering. The high crystalline quality of the FeGe films was confirmed by
x-ray diffraction and scanning transmission electron microscopy. Hall effect
measurements reveal strong topological Hall effect after subtracting out the
ordinary and anomalous Hall effects, demonstrating the formation of high
density skyrmions in FeGe films between 5 and 275 K. In particular, substantial
topological Hall effect was observed at zero magnetic field, showing a robust
skyrmion phase without the need of an external magnetic field.


title:
Evaluating Journal Quality: A Review of Journal Citation Indicators and
  Ranking in Business and Management

abstract:
  Evaluating the quality of academic journal is becoming increasing important
within the context of research performance evaluation. Traditionally, journals
have been ranked by peer review lists such as that of the Association of
Business Schools (UK) or though their journal impact factor (JIF). However,
several new indicators have been developed, such as the h-index, SJR, SNIP and
the Eigenfactor which take into account different factors and therefore have
their own particular biases. In this paper we evaluate these metrics both
theoretically and also through an empirical study of a large set of business
and management journals. We show that even though the indicators appear highly
correlated in fact they lead to large differences in journal rankings. We
contextualize our results in terms of the UK's large scale research assessment
exercise (the RAE/REF) and particularly the ABS journal ranking list. We
conclude that no one indicator is superior but that the h-index (which includes
the productivity of a journal) and SNIP (which aims to normalize for field
effects) may be the most effective at the moment.


title: Discrete fractional Fourier transform: Vandermonde approach

abstract:
  Based on the definition of the Fourier transform in terms of the number
operator of the quantum harmonic oscillator and in the corresponding definition
of the fractional Fourier transform, we have obtained the discrete fractional
Fourier transform from the discrete Fourier transform in a completely analogous
manner. To achieve this, we have used a very simple method based on the
Vandermonde matrices, to obtain rational and irrational powers of the discrete
Fourier transform matrices.


title:
Faster Average Case Low Memory Semi-External Construction of the
  Burrows-Wheeler Transform

abstract:
  The Burrows Wheeler transform has applications in data compression as well as
full text indexing. Despite its important applications and various existing
algorithmic approaches the construction of the transform for large data sets is
still challenging. In this paper we present a new semi external memory
algorithm for constructing the Burrows Wheeler transform. It is capable of
constructing the transform for an input text of length $n$ over a finite
alphabet in time $O(n\log^2\log n)$ on average, if sufficient internal memory
is available to hold a fixed fraction of the input text. In the worst case the
run-time is $O(n\log n \log\log n)$. The amount of space used by the algorithm
in external memory is $O(n)$ bits. Based on the serial version we also present
a shared memory parallel algorithm running in time
$O(\frac{n}{p}\max\{\log^2\log n+\log p\})$ on average when $p$ processors are
available.


title: Intersection norms on surfaces and Birkhoff cross sections

abstract:
  For every finite collection of curves on a surface, we define an associated
(semi-)norm on the first homology group of the surface. The unit ball of the
dual norm is the convex hull of its integer points. We give an interpretation
of these points in terms of certain coorientations of the original collection
of curves. Our main result is a classification statement: when the surface has
constant curvature and the curves are geodesics, integer points in the interior
of the dual unit ball classify isotopy classes of Birkhoff cross sections for
the geodesic flow (on the unit tangent bundle to the surface) whose boundary is
the symmetric lift of the collection of geodesics. Birkhoff cross sections in
particular yield open-book decompositions of the unit tangent bundle.


title:
On the dynamics of Riccati foliations with non parabolic monodromy
  representations

abstract:
  In this paper, we study the dynamics of Riccati foliations over non-compact
finite volume Riemann surfaces. More precisely, we are interested in two
closely related questions: the asymptotic behaviour of the holonomy map Hol t
($\omega$) defined for every time t over a generic Brownian path $\omega$ in
the base; and the analytic continuation of holonomy germs of the foliation
along Brownian paths in transversal lines. When the monodromy representation is
parabolic (i.e. the monodromy around any puncture is a parabolic element in P
SL 2 (C)), these questions have already been solved in [DD2] and [Hus]. Here,
we study the more general case where some puncture have hyperbolic monodromy.
We characterise the lower-upper, upper-upper and upper-lower classes of the map
Hol t ($\omega$) for almost every Brownian path $\omega$. And we prove that the
main result of [Hus] still holds in this case: when the monodromy group is "big
enough" , any holonomy germ of the foliations between two lines can be
analytically continued along a generic Brownian path.


title: Stark-Wannier Ladders and Cubic Exponential Sums

abstract:
  On L 2 (R), we consider the Schr\"odinger operator (1.1) H \k{o} = --
$\partial$ 2 $\partial$x 2 + v(x) -- \k{o}x, where v is a real analytic
1-periodic function and \k{o} is a positive constant. This operator is a model
to study a Bloch electron in a constant electric field ([1]). The parameter
\k{o} is proportional to the electric field. The operator (1.1) was studied
both by physicists (see, e.g., the review [6]) and by mathematicians (see,
e.g., [9]). Its spectrum is absolutely continuous and fills the real axis. One
of main features of H \k{o} is the existence of Stark-Wannier ladders. These
are \k{o}-periodic sequences of resonances, which are poles of the analytic
continuation of the resolvent kernel in the lower half plane through the
spectrum (see, e.g., [2]). Most of the mathematical work studied the case of
small \k{o} (see, e.g., [9, 3] and references therein). When \k{o} is small,
there are ladders exponentially close to the real axis. Actually, only the case
of finite gap potentials v was relatively well understood. For these
potentials, there is only a finite number of ladders exponentially close to the
real axis. It was further noticed that the ladders non-trivially "interact" as
\k{o} changes, and conjectured that the behavior of the resonances strongly
depends on number theoretical properties of \k{o} (see, e.g., [1]). In the
present note, we only consider the periodic potential v(x) = 2 cos(2$\pi$x) and
study the reflection coefficient r(E) of the Stark-Wannier operator (1.1) in
the lower half of the complex plane of the spectral parameter E. The resonances
are the poles of the reflection coefficient. We show that, as Im E
$\rightarrow$ --$\infty$, the function E $\rightarrow$ 1 r(E) can be
asymptotically described in terms of a regularized cubic exponential sum that
is a close relative of the cubic exponential sums often encountered in analytic
number theory. This explains the dependence of the reflection coefficient on
the arithmetic.


title:
An Optimized Combination of a Large Grid Connected PV System along with
  Battery Cells and a Diesel Generator

abstract:
  Environmental, economical and technical benefits of photovoltaic (PV) systems
make them to be used in many countries. The main characteristic of PV systems
is the fluctuations of their output power. Hence, high penetration of PV
systems into electric network could be detrimental to overall system
performance. Furthermore, the fluctuations in the output power of PV systems
make it difficult to predict their output, and to consider them in generation
planning of the units. The main objective of this paper is to propose a hybrid
method which can be used to control and reduce the power fluctuations generated
from large grid- connected PV systems. The proposed method focuses on using a
suitable storage battery along with curtailment of the generated power by
operating the PV system below the maximum power point (MPP) and deployment of a
diesel generator. These methods are analyzed to investigate the impacts of
implementing them on the economical benefits that the PV system owner could
gain. To maximize the revenues, an optimization problem is solved.


title:
Dynamical chiral symmetry breaking and weak nonperturbative
  renormalization group equation in gauge theory

abstract:
  We analyze the dynamical chiral symmetry breaking in gauge theory with the
nonperturbative renormalization group equation (NPRGE), which is a first order
nonlinear partial differential equation (PDE). In case that the spontaneous
chiral symmetry breaking occurs, the NPRGE encounters some non-analytic
singularities at the finite critical scale even though the initial function is
continuous and smooth. Therefore there is no usual solution of the PDE beyond
the critical scale. In this paper, we newly introduce the notion of a weak
solution which is the global solution of the weak NPRGE. We show how to
evaluate the physical quantities with the weak solution.


title: On a two-particle bound system on the half-line

abstract:
  In this paper we provide an extension of the model discussed in
[arXiv:1504.08283] describing two singularly interacting particles on the
half-line. In this model, the particles are interacting only whenever at least
one particle is situated at the origin. Stimulated by [arXiv:1503.08814] we
then provide a generalisation of this model in order to include additional
interactions between the particles leading to a molecular-like state. We give a
precise mathematical formulation of the Hamiltonian of the system and perform
spectral analysis. In particular, we are interested in the effect of the
singular two-particle interactions onto the molecule.

categories: math-ph cond-mat.mes-hall cond-mat.supr-con math.MP math.SP quant-ph


title: A mesoscopic field theoretical approach for active systems

abstract:
  We introduce a mesocopic modeling approach for active systems. The continuum
model allows to consider microscopic details as well as emerging macroscopic
behavior and can be considered as a minimal continuum model to describe generic
properties of active systems with isotropic agents. The model combines aspects
from phase field crystal (PFC) models and Toner-Tu models. The results are
validated by reproducing results obtained with corresponding agent-based
microscopic models. We consider binary collisions, collective motion and vortex
formation. For larger numbers of particles we analyze the coarsening process in
active crystals and identify giant number fluctuation in the cluster formation
process.


title:
On upper and lower bounds for finite group actions on bounded surfaces,
  handlebodies, closed handles and finite graphs

abstract:
  This is a survey on upper and lower bounds for finite group actions on
bounded surfaces, 3-dimensional handlebodies and closed handles, handlebodies
in arbitrary dimensions and finite graphs (the common feature of these objects
is that all have free fundamental group).


title:
Radiation from laser-microplasma-waveguide interactions in the
  ultra-intense regime

abstract:
  When a high-contrast ultra-relativistic laser beam enters a micro-sized
plasma waveguide, the pulse energy is coupled into waveguide modes, which
remarkably modifies the interaction of electrons and electromagnetic wave. The
electrons that pulled out of walls form a dense helical bunch inside the
channel are efficiently accelerated by the transverse magnetic modes to
hundreds of MeVs. In the mean time, the asymmetry in the transverse electric
and magnetic fields provides significant wiggling that leads to a bright,
well-collimated emission of hard X-rays. In this paper, we present our study on
the underlying physics in the aforementioned process using 3D particle-in-cell
simulations. The mechanism of electron acceleration and the dependence of
radiation properties on different laser plasma parameters are addressed. A
theoretical analysis model and basic scalings for X-ray emission are also
presented by considering the lowest optical modes in the waveguide, which is
adequate to describe the basic observed phenomenon. In addition, the effects of
high order modes as well as laser polarization are also qualitatively
discussed. The considered X-ray source have promising features that might serve
as a competitive candidate for future tabletop synchrotron source.


title: BlockQuicksort: How Branch Mispredictions don't affect Quicksort

abstract:
  Since the work of Kaligosi and Sanders (2006), it is well-known that
Quicksort -- which is commonly considered as one of the fastest in-place
sorting algorithms -- suffers in an essential way from branch mispredictions.
We present a novel approach to address this problem by partially decoupling
control from data flow: in order to perform the partitioning, we split the
input in blocks of constant size (we propose 128 data elements); then, all
elements in one block are compared with the pivot and the outcomes of the
comparisons are stored in a buffer. In a second pass, the respective elements
are rearranged. By doing so, we avoid conditional branches based on outcomes of
comparisons at all (except for the final Insertionsort). Moreover, we prove
that for a static branch predictor the average total number of branch
mispredictions is at most $\epsilon n \log n + O(n)$ for some small $\epsilon$
depending on the block size when sorting $n$ elements.
  Our experimental results are promising: when sorting random integer data, we
achieve an increase in speed of 80% over the GCC implementation of C++
std::sort. Also for many other types of data and non-random inputs, there is
still a significant speedup over std::sort. Only in few special cases like
sorted or almost sorted inputs, std::sort can beat out implementation.
Moreover, even on random input permutations, our implementation is even
slightly faster than an implementation of the highly tuned Super Scalar Sample
Sort, which uses a linear amount of additional space.


title: On Single Particle Energies and Nuclear g Factors

abstract:
  If we add one neutron to doubly magic ^{100}Sn, we can associate the low
lying states in^{101} Sn with single particle states.The the J=5/2^{+} and J=
7/2^{+} states are identified as d_{5/2}and g_{7/2}states respectively...They
are separated by an energy of 0.18 MeV.Unfortunately there is a disputeas to
the ordering of these states.We examine how the 2 scenarios-- J=5/2^{+} ground
state or J=7/2^{+}ground state-- affect spectra of higher Sn isotopes .


title: Four-dimensional unsubtraction from the loop-tree duality

abstract:
  We present a new algorithm to construct a purely four dimensional
representation of higher-order perturbative corrections to physical
cross-sections at next-to-leading order (NLO). The algorithm is based on the
loop-tree duality (LTD), and it is implemented by introducing a suitable
mapping between the external and loop momenta of the virtual scattering
amplitudes, and the external momenta of the real emission corrections. In this
way, the sum over degenerate infrared states is performed at integrand level
and the cancellation of infrared divergences occurs locally without introducing
subtraction counter-terms to deal with soft and final-state collinear
singularities. The dual representation of ultraviolet counter-terms is also
discussed in detail, in particular for self-energy contributions. The method is
first illustrated with the scalar three-point function, before proceeding with
the calculation of the physical cross-section for $\gamma^* \to q \bar{q}(g)$,
and its generalisation to multi-leg processes. The extension to
next-to-next-to-leading order (NNLO) is briefly commented.


title:
Electron Interaction Effects in Periodically Driven Kitaev Model:
  Topology Breaking and Enhancement of Quantum Chaos

abstract:
  The effect of electron-electron interaction on Floquet topological
superconducting chains is investigated numerically through full diagonalization
and time evolution. The preservation of topology in the weak interacting regime
is represented by a many-body form of the Majorana survival probability, and
the emergence of chaos is characterized using the level statistics. In the
presence of weak interaction, there appear a multitude of avoided crossings in
quasi-energy spectra, and the resulting chaos is not full but can coexist with
the topology. Strong interaction will lead the system into a topologically
trivial and fully chaotic phase.


title: Magnetic cycles at different ages of stars

abstract:
  We study the different patterns of interannual magnetic variability in stars
on or near the lower main sequence, approximately solar-type (G-K dwarf) stars
in time series of 36 years from the Mount Wilson Observatory Ca\,{\sc ii}\,H\&K
survey. Our main aim is to search for correlations between cycles, activity
measures and ages. Time-frequency analysis has been used to discern and reveal
patterns and morphology of stellar activity cycles, including multiple and
changing cycles, in the datasets. Both the results from short-term Fourier
transform and its refinement using the Choi-Williams distribution, with better
frequency resolution, are presented in this study. Rotational periods of the
stars were derived using multi-frequency Fourier analysis.From the studied 29
stars we found at least one activity cycle on 28 of them. Twelve stars, with
longer rotational periods ($39.7\pm6.0$ days) have simple, smooth cycles, and
the rest of the stars, with on-average much faster rotation ($18.1\pm12.2$
days) show complex and sometimes vigorously changing, multiple cycles. The
cycles are longer and quite uniform in the first group ($9.7\pm1.9$ years),
while are generally shorter and with greater variety in the second one
($7.6\pm4.9$). There is a clear age division between stars with smooth and
complex cycles that follows the known separation between the older and younger
stars at around 2 to 3~Gyr of age.


title: Uncertainty relations on nilpotent Lie groups

abstract:
  We give relations between main operators of quantum mechanics on one of most
general classes of nilpotent Lie groups. Namely, we show relations between
momentum and position operators as well as Euler and Coulomb potential
operators on homogeneous groups. Homogeneous group analogues of some well-known
inequalities such as Hardy's inequality, Heisenberg-Kennard type and
Heisenberg-Pauli-Weyl type uncertainty inequalities, as well as
Caffarelli-Kohn-Nirenberg inequality are derived, with best constants. The
obtained relations yield new results already in the setting of both isotropic
and anisotropic $\mathbb R^{n}$, and of the Heisenberg group.


title:
The class of the affine line is a zero divisor in the Grothendieck ring:
  an improvement

abstract:
  Lev A. Borisov has shown that the class of the affine line is a zero divisor
in the Grothendieck ring of algebraic varieties over complex numbers. We
improve the final formula by removing a factor.


title: Massive gravitons as dark matter and gravitational waves

abstract:
  We consider the possibility that the massive graviton is a viable candidate
of dark matter in the context of bimetric gravity. We first derive the
energy-momentum tensor of the massive graviton and show that it indeed behaves
as that of dark matter fluid. We then discuss a production mechanism and the
present abundance of massive gravitons as dark matter. Since the metric to
which ordinary matter fields couple is a linear combination of the two mass
eigenstates of bigravity, production of massive gravitons, i.e. the dark matter
particles, is inevitably accompanied by generation of massless gravitons, i.e.
the gravitational waves. Therefore, in this scenario some information about
dark matter in our universe is encoded in gravitational waves. For instance, if
LIGO detects gravitational waves generated by the preheating after inflation
then the massive graviton with the mass of $\sim 0.01$ GeV is a candidate of
the dark matter.


title:
Spectral study of GX 339-4 with TCAF using Swift/XRT and NuSTAR
  Observation

abstract:
  We fit spectra of galactic transient source GX~339-4 during its 2013 outburst
using Two Component Advective Flow (TCAF) solution. For the first time, we are
fitting combined NuSTAR and Swift observation with TCAF. We use TCAF to fit
0.8-9.0~keV Swift and 4-79 keV NuSTAR spectra along with the LAOR model. To fit
the data we use disk accretion rate, halo accretion rate, size of the Compton
cloud and the density jump of advective flows at this cloud boundary as model
parameters. From TCAF fitted flow parameters, and energy spectral index we
conclude that the source was in the hard state throughout this particular
outburst. The present analysis also gives some idea about the broadening of Fe
$K_{\alpha}$ with the accretion rate. Since TCAF does not include Fe line yet,
we make use of the `LAOR model' as a phenomenological model and find an
estimate of the Kerr parameter to be $\sim 0.99$ for this candidate.


title:
Octupole correlations in the nucleus $^{144}$Ba described with symmetry
  conserving configuration mixing calculations

abstract:
  We study the interplay of quadrupole and octupole degrees of freedom in the
structure of the isotope $^{144}$Ba. A symmetry conserving configuration mixing
method (SCCM) based on a Gogny energy density functional (EDF) has been used.
The method includes particle number, parity and angular momentum restoration as
well as axial quadrupole and octupole shape mixing within the generator
coordinate method. Predictions both for excitation energies and electromagnetic
transition probabilities are in good agreement with the most recent
experimental data.


title: Loopless Gray Code Enumeration and the Tower of Bucharest

abstract:
  We give new algorithms for generating all n-tuples over an alphabet of m
letters, changing only one letter at a time (Gray codes). These algorithms are
based on the connection with variations of the Towers of Hanoi game. Our
algorithms are loopless, in the sense that the next change can be determined in
a constant number of steps, and they can be implemented in hardware. We also
give another family of loopless algorithms that is based on the idea of working
ahead and saving the work in a buffer.


title:
Analytic Solutions of Von Karman Plate under Arbitrary Uniform Pressure
  --- Equations in Differential Form

abstract:
  The large deflection of a circular thin plate under uniform external pressure
is a classic problem in solid mechanics, dated back to Von K{\'a}rm{\'a}n
\cite{Karman}. {This problem is reconsidered in this paper using an analytic
approximation method, namely the homotopy analysis method (HAM).} Convergent
series solutions are obtained for four types of boundary conditions with rather
high nonlinearity, even in the case of $w(0)/h>20$, where $w(0)/h$ denotes the
ratio of central deflection to plate thickness. Especially, we prove that the
previous perturbation methods for an arbitrary perturbation quantity (including
the Vincent's [2] and Chien's [3] methods) and the modified iteration method
[4] are only the special cases of the HAM. However, the HAM works well even
when the perturbation methods become invalid. All of these demonstrate the
validity and potential of the HAM for the Von K{\'a}rm{\'a}n's plate equations,
and show the superiority of the HAM over perturbation methods for highly
nonlinear problems


title: FeynCalc 9

abstract:
  We report on a new version of FeynCalc, a well-known Mathematica package for
symbolic computations in quantum field theory and provide some explicit
examples for using the software in different types of calculations.


title:
Using Reinforcement Learning to Validate Empirical Game-Theoretic
  Analysis: A Continuous Double Auction Study

abstract:
  Empirical game-theoretic analysis (EGTA) has recently been applied
successfully to analyze the behavior of large numbers of competing traders in a
continuous double auction market. Multiagent simulation methods like EGTA are
useful for studying complex strategic environments like a stock market, where
it is not feasible to solve analytically for the rational behavior of each
agent. A weakness of simulation-based methods in strategic settings, however,
is that it is typically impossible to prove that the strategy profile assigned
to the simulated agents is stable, as in a Nash equilibrium. I propose using
reinforcement learning to analyze the regret of supposed Nash-equilibrium
strategy profiles found by EGTA. I have developed a new library of
reinforcement learning tools, which I have integrated into an extended version
of the market simulator from our prior work. I provide evidence for the
effectiveness of our library methods, both on a suite of benchmark problems
from the literature, and on non-equilibrium strategy profiles in our market
environment. Finally, I use our new reinforcement learning tools to provide
evidence that the equilibria found by EGTA in our recent continuous double
auction study are likely to have only negligible regret, even with respect to
an extended strategy space.


title:
Analytic Solutions of Von Karman Plate under Arbitrary Uniform Pressure
  (II): Equations in Integral Form

abstract:
  In this paper, the homotopy analysis method (HAM) is successfully applied to
solve the Von Karman's plate equations in the integral form for a circular
plate with the clamped boundary under an arbitrary uniform external pressure.
Two HAM-based approaches are proposed. One is for a given external load Q, the
other for a given central deflection. Both of them are valid for an arbitrary
uniform external pressure by means of choosing a proper value of the so-called
convergence-control parameters c_1 and c_2 in the frame of the HAM. Besides, it
is found that iteration can greatly accelerate the convergence of solution
series. In addition, we prove that the interpolation iterative method is a
special case of the HAM-based 1st-order iteration approach for a given external
load Q when c_1=-theta and c_2=-1, where theta denotes the interpolation
parameter of the interpolation iterative method. Therefore, like Zheng and
Zhou}, one can similarly prove that the HAM-based approaches are valid for an
arbitrary uniform external pressure, at least in some special cases such as
c_1=-theta and c_2=-1. Furthermore, it is found that the HAM-based iteration
approaches converge much faster than the interpolation iterative method. All of
these illustrate the validity and potential of the HAM for the famous Von
Karman's plate equations, and show the superiority of the HAM over perturbation
methods.


title:
Thermal dilepton rates and electrical conductivity of the QGP from the
  lattice

abstract:
  We investigate the temperature dependence of the thermal dilepton rate and
the electrical conductivity of the gluon plasma at temperatures of $1.1T_c$,
$1.3T_c$ and $1.5T_c$ in quenched QCD. Making use of non-perturbatively
clover-improved Wilson valence quarks allows for a clean extrapolation of the
vector meson correlation function to the continuum limit. We found that the
vector correlation function divided by $T^3$ is almost temperature independent
in the current temperature window. The spectral functions are obtained by
$\chi^2$ fitting of phenomenologically inspired Ans\"atze for the spectral
function to the continuum extrapolated correlator data, where the correlations
between the data points have been included. Systematic uncertainties arising
from varying the Ans\"atze motivated from strong coupling theory as well as
perturbation theory are discussed and estimated. We found that the electrical
conductivity of the hot medium, related to the slope of the vector spectral
function at zero frequency and momentum, is $0.2C_{em}\lesssim
\sigma/T\lesssim0.7C_{em}$ for $T=1.1T_c$ and $0.2C_{em}\lesssim
\sigma/T\lesssim0.4C_{em}$ for the higher temperatures. The dilepton rates and
soft photon rates, resulting from the obtained spectral functions, show no
significant temperature dependence, either.


title: The expected neutral frequency spectrum of linked sites

abstract:
  We present an exact, closed expression for the expected neutral Site
Frequency Spectrum for two neutral sites, 2-SFS, without recombination. This
spectrum is the immediate extension of the well known single site $\theta/f$
neutral SFS. Similar formulae are also provided for the case of the expected
SFS of sites that are linked to a focal neutral mutation of known frequency.
Formulae for finite samples are obtained by coalescent methods and remarkably
simple expressions are derived for the SFS of a large population, which are
also solutions of the multi-allelic Kolmogorov equations. Besides the general
interest of these new spectra, they relate to interesting biological cases such
as structural variants and introgressions. As an example, we present the
expected neutral frequency spectrum of regions with a chromosomal inversion.


title:
Study on Neural Immune PD Type Tracking Control for DC Actuating
  Mechanism

abstract:
  Artificial Immune Systems(AIS) have been widely used in different fields,
such as control, robotics, computer science and multi-agent systems. In this
paper is proposed a new approach of neural immune PD type tracking control
combining artificial immune control with neural network. It is assumed that the
output of the helper T-cell is concerned with not only the error of system but
also its changing rate, while the output of suppressor T-cell is unknown
nonlinear function with respect to the amount and changing rate of antigens and
the changing rate of antibodies, which is approximated by the output of neural
network. From this, we derive neural immune PD type control law and apply it to
the trajectory tracking of DC actuating mechanism. The validity of the proposed
method is verified by simulation and the simulation results show that this
method can follow the desired trajectory more rapidly and more accurately
compared to the previous method.


title: Parameterized Compilation Lower Bounds for Restricted CNF-formulas

abstract:
  We show unconditional parameterized lower bounds in the area of knowledge
compilation, more specifically on the size of circuits in decomposable negation
normal form (DNNF) that encode CNF-formulas restricted by several graph width
measures. In particular, we show that
  - there are CNF formulas of size $n$ and modular incidence treewidth $k$
whose smallest DNNF-encoding has size $n^{\Omega(k)}$, and
  - there are CNF formulas of size $n$ and incidence neighborhood diversity $k$
whose smallest DNNF-encoding has size $n^{\Omega(\sqrt{k})}$.
  These results complement recent upper bounds for compiling CNF into DNNF and
strengthen---quantitatively and qualitatively---known conditional low\-er
bounds for cliquewidth. Moreover, they show that, unlike for many graph
problems, the parameters considered here behave significantly differently from
treewidth.


title:
Supplementary Material for "Should we sample a time series more
  frequently? Decision support via multirate spectrum estimation (with
  discussion)"

abstract:
  This technical report includes an assortment of technical details and
extended discussions related to paper "Should we sample a time series more
frequently? Decision support via multirate spectrum estimation (with
discussion)", which introduces a model for estimating the log-spectral density
of a stationary discrete time process given systematically missing data and
models the cost implication for changing the sampling rate.


title:
First evidence for a Sm$^{3+}$-type contribution to the magnetic form
  factor in the quasielastic spectral response of intermediate valence
  SmB$_{6}$

abstract:
  The momentum transfer dependence of the magnetic form factor associated with
the quasielastic spectral component in the dynamic magnetic response of
intermediate valence SmB$_{6}$ has been measured using inelastic neutron
scattering on a double-isotope ($^{154}$Sm, $^{11}$B) single crystal. The
experimental dependence differs qualitatively from those obtained earlier for
the inelastic signals, as well as from the field-induced magnetic form factor
of SmB$_{6}$ obtained by polarized neutron diffraction. This observation is
interpreted by specifically considering the Curie-type contributions to the
dynamic susceptibility, which arise from the mixing of 4f$^{5}$ and 4f$^{6}$
J-multiplets into the intermediate valence state wave function.


title: Perforation conditions and almost algebraic order in Cuntz semigroups

abstract:
  For a C$^*$-algebra $A$, it is an important problem to determine the Cuntz
semigroup $\mathrm{Cu}(A\otimes\mathcal{Z})$ in terms of $\mathrm{Cu}(A)$. We
approach this problem from the point of view of semigroup tensor products in
the category of abstract Cuntz semigroups, by analysing the passage of
significant properties from $\mathrm{Cu}(A)$ to
$\mathrm{Cu}(A)\otimes_\mathrm{Cu}\mathrm{Cu}(\mathcal{Z})$. We describe the
effect of the natural map
$\mathrm{Cu}(A)\to\mathrm{Cu}(A)\otimes_\mathrm{Cu}\mathrm{Cu}(\mathcal{Z})$ in
the order of $\mathrm{Cu}(A)$, and show that, if $A$ has real rank zero and no
elementary subquotients,
$\mathrm{Cu}(A)\otimes_\mathrm{Cu}\mathrm{Cu}(\mathcal{Z})$ enjoys the
corresponding property of having a dense set of (equivalence classes of)
projections. In the simple, nonelementary, real rank zero and stable rank one
situation, our investigations lead us to identify almost unperforation for
projections with the fact that tensoring with $\mathcal{Z}$ is inert at the
level of the Cuntz semigroup.


title:
Correspondence: Enhancing a phase measurement by sequentially probing a
  solid state system

abstract:
  In a recent paper, Liu et al. [Nat. Commun. 6:6726 (2015)] claim to perform
the first room temperature entanglement-enhanced phase measurement in a
solid-state system. We argue here that this claim is incorrect: their
measurement is not enhanced because of the entanglement in their system, but
instead the enhancement comes from the fact that the phase shift is applied
twice to their state.


title:
Learning rotation invariant convolutional filters for texture
  classification

abstract:
  We present a method for learning discriminative filters using a shallow
Convolutional Neural Network (CNN). We encode rotation invariance directly in
the model by tying the weights of groups of filters to several rotated versions
of the canonical filter in the group. These filters can be used to extract
rotation invariant features well-suited for image classification. We test this
learning procedure on a texture classification benchmark, where the
orientations of the training images differ from those of the test images. We
obtain results comparable to the state-of-the-art. Compared to standard shallow
CNNs, the proposed method obtains higher classification performance while
reducing by an order of magnitude the number of parameters to be learned.


title:
Exploiting Deep Semantics and Compositionality of Natural Language for
  Human-Robot-Interaction

abstract:
  We develop a natural language interface for human robot interaction that
implements reasoning about deep semantics in natural language. To realize the
required deep analysis, we employ methods from cognitive linguistics, namely
the modular and compositional framework of Embodied Construction Grammar (ECG)
[Feldman, 2009]. Using ECG, robots are able to solve fine-grained reference
resolution problems and other issues related to deep semantics and
compositionality of natural language. This also includes verbal interaction
with humans to clarify commands and queries that are too ambiguous to be
executed safely. We implement our NLU framework as a ROS package and present
proof-of-concept scenarios with different robots, as well as a survey on the
state of the art.


title:
Finding and proving the exact ground state of a generalized Ising model
  by convex optimization and MAX-SAT

abstract:
  Lattice models, also known as generalized Ising models or cluster expansions,
are widely used in many areas of science and are routinely applied to alloy
thermodynamics, solid-solid phase transitions, magnetic and thermal properties
of solids, and fluid mechanics, among others. However, the problem of finding
the true global ground state of a lattice model, which is essential for all of
the aforementioned applications, has remained unresolved, with only a limited
number of results for highly simplified systems known. In this article, we
present the first general algorithm to find the exact ground states of complex
lattice models and to prove their global optimality, resolving this fundamental
problem in condensed matter and materials theory. We transform the
infinite-discrete-optimization problem into a pair of combinatorial
optimization (MAX-SAT) and non-smooth convex optimization (MAX-MIN) problems,
which provide upper and lower bounds on the ground state energy respectively.
By systematically converging these bounds to each other, we find and prove the
exact ground state of realistic Hamiltonians whose solutions are completely
intractable via traditional methods. Considering that currently such
Hamiltonians are solved using simulated annealing and genetic algorithms that
are often unable to find the true global energy minimum, and never able to
prove the optimality of their result, our work opens the door to resolving
long-standing uncertainties in lattice models of physical phenomena.

categories: cond-mat.dis-nn cond-mat.stat-mech math-ph math.MP physics.comp-ph


title: Refining Lagrange's four-square theorem

abstract:
  Lagrange's four-square theorem asserts that any $n\in\mathbb
N=\{0,1,2,\ldots\}$ can be written as the sum of four squares. This can be
further refined in various ways. We show that any $n\in\mathbb N$ can be
written as $x^2+y^2+z^2+w^2$ with $x,y,z,w\in\mathbb Z$ such that $x+y+z$ (or
$x+2y$, $x+y+2z$) is a square (or a cube). We also prove that any $n\in\mathbb
N$ can be written as $x^2+y^2+z^2+w^2$ with $x,y,z,w\in\mathbb N$ such that
$P(x,y,z)$ is a square, whenever $P(x,y,z)$ is among the polynomials
\begin{gather*} x,\ 2x,\ x-y,\ 2x-2y,\ a(x^2-y^2)\ (a=1,2,3),\ x^2-3y^2,\
3x^2-2y^2, \\x^2+ky^2\ (k=2,3,5,6,8,12),\ (x+4y+4z)^2+(9x+3y+3z)^2,
\\x^2y^2+y^2z^2+z^2x^2,\ x^4+8y^3z+8yz^3, x^4+16y^3z+64yz^3. \end{gather*} We
also pose some conjectures for further research; for example, our
1-3-5-Conjecture states that any $n\in\mathbb N$ can be written as
$x^2+y^2+z^2+w^2$ with $x,y,z,w\in\mathbb N$ such that $x+3y+5z$ is a square.


title: Maximally restrictive leptonic texture zeros in two-Higgs-doublet models

abstract:
  The implementation of maximally restrictive texture zeros in the leptonic
sector is investigated in the context of two-Higgs-doublet models with Majorana
neutrinos. After analyzing all maximally restrictive pairs of leptonic mass
matrices with zero entries, we conclude that there are only four texture
combinations that are compatible with observations at 3 sigma confidence level
and can be implemented through Abelian symmetries in a two-Higgs-doublet model.
The compatibility of these textures with current constraints on
lepton-flavor-violating processes is also studied. The ultraviolet completion
of these models is discussed in the framework of the seesaw mechanism for
neutrino masses.


title: CHANG-ES VII: Magnetic outflows from the Virgo cluster galaxy NGC 4388

abstract:
  We investigate the effects of ram pressure on the ordered magnetic field of a
galaxy hosting a radio halo and strong nuclear outflows. New radio images in
total and polarized intensity of the edge-on Virgo galaxy NGC\,4388 were
obtained within the CHANG-ES EVLA project. The unprecedented noise level
reached allows us to detect striking new features of the ordered magnetic
field. The nuclear outflow extends far into the halo to about 5\,kpc from the
center and is spatially correlated with the $\rm{H}\alpha$ and X-ray emission.
For the first time, the southern outflow is detected. Above and below both
spiral arms we find extended blobs of polarized emission with an ordered field
oriented perpendicular to the disk. The synchrotron lifetime of the cosmic ray
electrons (CREs) in these regions yields a mean outflow velocity of
$(270\pm70)\kms$, in agreement with a galactic wind scenario. The observed
symmetry of the polarized halo features in NGC 4388 excludes a compression of
the halo gas by the ram pressure of the intra-cluster medium (ICM). The
assumption of equilibrium between the halo pressure and the ICM ram pressure
yields an estimate of the ICM density that is consistent with both the ICM
density derived from X-ray observations and the recent \textit{Planck}
Sunyaev-Zel'dovich measurements. The detection of a faint radio halo around
cluster galaxies could thus be used for an estimate of ICM ram pressure.


title:
Shot noise reduced terahertz detection via spectrally post-filtered
  electro-optic sampling

abstract:
  In ultrabroadband terahertz electro-optic sampling, spectral filtering of the
gate pulse can strongly reduce the quantum noise while the signal level is only
weakly affected. The concept is tested for phase-matched electro-optic
detection of field transients centered at 45 THz with 12-fs near-infrared gate
pulses in AgGaS2. Our new approach increases the experimental signal-to-noise
ratio by a factor of 3 compared to standard electro-optic sampling. Under
certain conditions an improvement factor larger than 5 is predicted by our
theoretical analysis.


title:
An improved chromosome formulation for genetic algorithms applied to
  variable selection with the inclusion of interaction terms

abstract:
  Genetic algorithms are a well-known method for tackling the problem of
variable selection. As they are non-parametric and can use a large variety of
fitness functions, they are well-suited as a variable selection wrapper that
can be applied to many different models. In almost all cases, the chromosome
formulation used in these genetic algorithms consists of a binary vector of
length n for n potential variables indicating the presence or absence of the
corresponding variables. While the aforementioned chromosome formulation has
exhibited good performance for relatively small n, there are potential problems
when the size of n grows very large, especially when interaction terms are
considered. We introduce a modification to the standard chromosome formulation
that allows for better scalability and model sparsity when interaction terms
are included in the predictor search space. Experimental results show that the
indexed chromosome formulation demonstrates improved computational efficiency
and sparsity on high-dimensional datasets with interaction terms compared to
the standard chromosome formulation.


title: New Combinatorial Formulas for Cluster Monomials of Type A Quivers

abstract:
  Lots of research focuses on the combinatorics behind various bases of cluster
algebras. This paper studies the natural basis of a type A cluster algebra,
which consists of all cluster monomials. We introduce a new kind of
combinatorial formulas for the cluster monomials in terms of the so-called
globally compatible collections. We give bijective proofs of these formulas by
comparing with the well-known combinatorial models of the T-paths and of the
perfect matchings in a snake diagram. For cluster variables of a type A cluster
algebra, we give a bijection that relates our new formula with the theta
functions constructed by Gross, Hacking, Keel and Kontsevich.


title:
A difference-equation formalism for the nodal domains of separable
  billiards

abstract:
  Recently, the nodal domain counts of planar, integrable billiards with
Dirichlet boundary conditions were shown to satisfy certain difference
equations in [Ann. Phys. 351, 1-12 (2014)]. The exact solutions of these
equations give the number of domains explicitly. For complete generality, we
demonstrate this novel formulation for three additional separable systems and
thus extend the statement to all integrable billiards.


title:
Developing an ICU scoring system with interaction terms using a genetic
  algorithm

abstract:
  ICU mortality scoring systems attempt to predict patient mortality using
predictive models with various clinical predictors. Examples of such systems
are APACHE, SAPS and MPM. However, most such scoring systems do not actively
look for and include interaction terms, despite physicians intuitively taking
such interactions into account when making a diagnosis. One barrier to
including such terms in predictive models is the difficulty of using most
variable selection methods in high-dimensional datasets. A genetic algorithm
framework for variable selection with logistic regression models is used to
search for two-way interaction terms in a clinical dataset of adult ICU
patients, with separate models being built for each category of diagnosis upon
admittance to the ICU. The models had good discrimination across all
categories, with a weighted average AUC of 0.84 (>0.90 for several categories)
and the genetic algorithm was able to find several significant interaction
terms, which may be able to provide greater insight into mortality prediction
for health practitioners. The GA selected models had improved performance
against stepwise selection and random forest models, and provides greater
flexibility in terms of variable selection by being able to optimize over any
modeler-defined model performance metric instead of a specific variable
importance metric.


title:
Extended scaling and residual flavor symmetry in the neutrino Majorana
  mass matrix

abstract:
  The residual symmetry approach, along with a complex extension for some
flavor invariance, is a powerful tool to uncover the flavor structure of the
$3\times3$ neutrino Majorana mass matrix $M_\nu$ towards gaining insights into
neutrino mixing. We utilize this to propose a complex extension of the real
scaling ansatz for $M_\nu$ which was introduced some years ago. Unlike the
latter, our proposal allows a nonzero mass for each of the three light
neutrinos as well as a nonvanishing $\theta_{13}$. A major result of this
scheme is that leptonic Dirac CP-violation must be maximal while atmospheric
neutrino mixing need not be exactly maximal. Moreover, each of the two allowed
Majorana phases, to be probed by the search for nuclear $0\nu \beta\beta$
decay, has to be at one of its two CP-conserving values. There are other
interesting consequences such as the allowed occurrence of a normal mass
ordering which is not favored by the real scaling ansatz. Our predictions will
be tested in ongoing and future neutrino oscillation experiments at T2K,
NO$\nu$A and DUNE.


title:
Effect of experimental parameters on optimal reflection of light from
  opaque media

abstract:
  Previously we considered the effect of experimental parameters on optimized
transmission through opaque media using spatial light modulator (SLM)-based
wavefront shaping. In this study we consider the opposite geometry, in which we
optimize reflection from an opaque surface such that the backscattered light is
focused onto a spot on an imaging detector. By systematically varying different
experimental parameters (genetic algorithm iterations, bin size, SLM active
area, target area, spot size, and sample angle with respect to the optical
axis) and optimizing the reflected light we determine how each parameter
affects the intensity enhancement. We find that the effects of the experimental
parameters on the enhancement are similar to those measured for a transmissive
geometry, but with the exact functional forms changed due to the different
geometry and the use of a genetic algorithm instead of an iterative algorithm.
Additionally, we find preliminary evidence of greater enhancements than
predicted by random matrix theory, suggesting a possibly new physical mechanism
to be investigated in future work.


title: Cascading Failures in AC Electricity Grids

abstract:
  Sudden failure of a single transmission element in a power grid can induce a
domino effect of cascading failures, which can lead to the isolation of a large
number of consumers or even to the failure of the entire grid. Here we present
results of the simulation of cascading failures in power grids, using an
alternating current (AC) model. We first apply this model to a regular square
grid topology. For a random placement of consumers and generators on the grid,
the probability to find more than a certain number of unsupplied consumers
decays as a power law and obeys a scaling law with respect to system size.
Varying the transmitted power threshold above which a transmission line fails
does not seem to change the power law exponent $q \approx 1.6$. Furthermore, we
study the influence of the placement of generators and consumers on the number
of affected consumers and demonstrate that large clusters of generators and
consumers are especially vulnerable to cascading failures. As a real-world
topology we consider the German high-voltage transmission grid. Applying the
dynamic AC model and considering a random placement of consumers, we find that
the probability to disconnect more than a certain number of consumers depends
strongly on the threshold. For large thresholds the decay is clearly
exponential, while for small ones the decay is slow, indicating a power law
decay.


title: Causal Linearizability

abstract:
  Most work on the verification of concurrent objects for shared memory assumes
sequential consistency, but most multicore processors support only weak memory
models that do not provide sequential consistency. Furthermore, most
verification efforts focus on the linearizability of concurrent objects, but
there are existing implementations optimized to run on weak memory models that
are not linearizable.
  In this paper, we address these problems by introducing causal
linearizability, a correctness condition for concurrent objects running on weak
memory models. Like linearizability itself, causal linearizability enables
concurrent objects to be composed, under weak constraints on the client's
behaviour. We specify these constraints by introducing a notion of
operation-race freedom, where programs that satisfy this property are
guaranteed to behave as if their shared objects were in fact linearizable.
  We apply these ideas to objects from the Linux kernel, optimized to run on
TSO, the memory model of the x86 processor family.


title:
Convergence Rates in Parabolic Homogenization with Time-Dependent
  Periodic Coefficients

abstract:
  For a family of second-order parabolic systems with bounded measurable,
rapidly oscillating and time-dependent periodic coefficients, we investigate
the sharp convergence rates of weak solutions in $L^2$. Both initial-Dirichlet
and initial-Neumann problems are studied.


title:
Strangeness production as a function of charged particle multiplicity in
  proton-proton collisions

abstract:
  Recent measurements performed in high-multiplicity proton-proton (pp) and
proton-lead (p-Pb) collisions have shown features that are reminiscent of those
observed in lead-lead (Pb-Pb) collisions. These observations warrant a
comprehensive measurement of the production of identified particles. We report
on the production of \allparts at mid-rapidity measured as a function of
multiplicity in pp collisions at $\sqrt{s}$ = 7 TeV with the ALICE experiment.
Spectral shapes studied both for individual particles and via particle ratios
such as ($\Lambda/K^{0}_{S}$) as a function of $p_{T}$ exhibit an evolution
with event multiplicity and the production rates of hyperons are observed to
increase more strongly than those of non-strange hadrons. These phenomena are
qualitatively similar to the ones observed in p-Pb and Pb-Pb collisions.


title: Entity Embeddings of Categorical Variables

abstract:
  We map categorical variables in a function approximation problem into
Euclidean spaces, which are the entity embeddings of the categorical variables.
The mapping is learned by a neural network during the standard supervised
training process. Entity embedding not only reduces memory usage and speeds up
neural networks compared with one-hot encoding, but more importantly by mapping
similar values close to each other in the embedding space it reveals the
intrinsic properties of the categorical variables. We applied it successfully
in a recent Kaggle competition and were able to reach the third position with
relative simple features. We further demonstrate in this paper that entity
embedding helps the neural network to generalize better when the data is sparse
and statistics is unknown. Thus it is especially useful for datasets with lots
of high cardinality features, where other methods tend to overfit. We also
demonstrate that the embeddings obtained from the trained neural network boost
the performance of all tested machine learning methods considerably when used
as the input features instead. As entity embedding defines a distance measure
for categorical variables it can be used for visualizing categorical data and
for data clustering.


title:
Damping Evaluation for Free Vibration of Spherical Structures in
  Elastodynamic-Acoustic Interaction

abstract:
  This paper discusses the free vibration of elastic spherical structures in
the presence of an externally unbounded acoustic medium. In this vibration,
damping associated with the radiation of energy from the confined solid medium
to the surrounding acoustic medium is observed. Evaluating the coupled system
response (solid displacement and acoustic pressure) and characterizing the
acoustic radiation damping in conjunction with the media properties are the
main objectives of this research. In this work, acoustic damping is
demonstrated for two problems: the thin spherical shell and the solid sphere.
The mathematical approach followed in solving these coupled problems is based
on the Laplace transform method. The linear under-damped harmonic oscillator is
the reference model for damping estimation. The damping evaluation is performed
in frequency as well as in time domains; both investigations lead to identical
damping factor expressions.


title: URAT Parallax Catalog (UPC)

abstract:
  The URAT Parallax Catalog (UPC) consists of 112,177 parallaxes. The catalog
utilizes all Northern Hemisphere exposures from the United States Naval
Observatory (USNO) Robotic Astrometric Telescope (URAT) obtained between April
2012 and June 2015. Relative parallaxes are converted to absolute using
photometric distance estimates of UCAC4 reference stars. There are 2 groups of
stars in this catalog: 1) 58,677 stars with prior published trigonometric
parallax (Hipparcos, Yale Parallax Catalog, MEarth project and SIMBAD), and 2)
53,500 stars with first time trigonometric parallaxes as obtained from URAT
data. More stringent selection criteria have been applied for group 2 then for
group 1 in order to keep the rate of false detections low. The mean error in
UPC parallaxes is 10.8 and 4.3 mas for groups 1 and 2, respectively. All stars
in UPC are north of -13 deg Dec and between 6.5 and 17 mag. The UPC is
published by CDS as catalog I/333 and the acronym has been registered with the
IAU. The Finch & Zacharias (2016, in press with AJ) paper describes the data,
reductions, and results of an about 1000 star subset (stars within 40 pc of the
Sun) of the entire UPC. The UPC also provides accurate positions and proper
motions on the ICRS. This is the largest parallax catalog published since the
Hipparcos Catalog.


title: Langevin equations for reaction-diffusion processes

abstract:
  For reaction-diffusion processes with at most bimolecular reactants, we
derive well-behaved, numerically tractable, exact Langevin equations that
govern a stochastic variable related to the response field in field theory.
Using duality relations, we show how the particle number and other quantities
of interest can be computed. Our work clarifies long-standing conceptual issues
encountered in field-theoretical approaches and paves the way for systematic
numerical and theoretical analyses of reaction-diffusion problems.


title:
The Incipient Giant Component in Bond Percolation on General Finite
  Weighted Graphs

abstract:
  On a large finite connected graph let edges $e$ become "open" at independent
random Exponential times of arbitrary rates $w_e$. Under minimal assumptions,
the time at which a giant component starts to emerge is weakly concentrated
around its mean.


title: Rydberg molecule-induced remote spin-flips

abstract:
  We have performed high resolution photoassociation spectroscopy of rubidium
ultra long-range Rydberg molecules in the vicinity of the 25$P$ state. Due to
the hyperfine interaction in the ground state perturber atom, the emerging
mixed singlet-triplet potentials contain contributions from both hyperfine
states. We show that this can be used to induce remote spin-flips in the
perturber atom upon excitation of a Rydberg molecule. When furthermore the
spin-orbit splitting of the Rydberg state is comparable to the hyperfine
splitting in the ground state, the orbital angular momentum of the Rydberg
electron is entangled with the nuclear spin of the perturber atom. Our results
open new possibilities for the implementation of spin-dependent interactions
for ultracold atoms in bulk systems and in optical lattices.


title:
Latent Contextual Bandits and their Application to Personalized
  Recommendations for New Users

abstract:
  Personalized recommendations for new users, also known as the cold-start
problem, can be formulated as a contextual bandit problem. Existing contextual
bandit algorithms generally rely on features alone to capture user variability.
Such methods are inefficient in learning new users' interests. In this paper we
propose Latent Contextual Bandits. We consider both the benefit of leveraging a
set of learned latent user classes for new users, and how we can learn such
latent classes from prior users. We show that our approach achieves a better
regret bound than existing algorithms. We also demonstrate the benefit of our
approach using a large real world dataset and a preliminary user study.


title:
Differential Reprogramming Based on Constructive Interference for
  Wireless Sensor Network

abstract:
  To improve the performance of reprogramming in wireless sensor network, we
present a novel reprogramming structure and constructive interference-based
dissemination protocol (CIDP) to transmit the patch through out the network
fast and reliability. CIDP disseminates the patch, which is divided into
several packets, to the network exploiting constructive interference. We
evaluate our implementation of CIDP using simulation under different number of
nodes. Our results show that CIDP disseminates the patch less than 4
milliseconds. In general, the probability of a node receives the complete patch
as high as 99.99%.


title: The Lorentz Force and Energy-Momentum for Off-Shell Electromagnetism

abstract:
  The kinematics of pre-Maxwell electrodynamics is examined and interpretations
of these fields is found through an examination of the associated Lorentz force
and the structure of the energy-momentum tensor.


title: Universal Effective Hadron Dynamics from Superconformal Algebra

abstract:
  An effective supersymmetric QCD light-front Hamiltonian for hadrons composed
of light quarks, which includes a spin-spin interaction between the hadronic
constituents, is constructed by embedding superconformal quantum mechanics into
AdS space. A specific breaking of conformal symmetry inside the graded algebra
determines a unique effective quark-confining potential for light hadrons, as
well as remarkable connections between the meson and baryon spectra. The
results are consistent with the empirical features of the light-quark hadron
spectra, including a universal mass scale for the slopes of the meson and
baryon Regge trajectories and a zero-mass pion in the limit of massless quarks.
Our analysis is consistently applied to the excitation spectra of the $\pi,
\rho, K, K^*$ and $\phi$ meson families as well as to the $N, \Delta, \Lambda,
\Sigma, \Sigma^*, \Xi$ and $\Xi^*$ in the baryon sector. We also predict the
existence of tetraquarks which are degenerate in mass with baryons with the
same angular momentum. The mass of light hadrons is expressed in a universal
and frame-independent decomposition in the semiclassical approximation
described here.


title: Generating Concurrency Checks Automatically

abstract:
  This article introduces ATAB, a tool that automatically generates pairwise
reachability checks for action trees. Action trees can be used to study the
behaviour of real-world concurrent programs. ATAB encodes pairwise reachability
checks into alternating tree automata that determine whether an action tree has
a schedule where any pair of given points in the program are simultaneously
reachable. Because the pairwise reachability problem is undecidable in general
ATAB operates under a restricted form of lock-based concurrency. ATAB produces
alternating tree automata that are more compact and more efficiently checkable
than those that have been previously used. The process is entirely automated,
which simplifies the process of encoding checks for more complex action trees.
The alternating tree automata produced are easier to scale to large numbers of
locks than previous constructions.


title: Molecular propensity as a driver for explorative reactivity studies

abstract:
  Quantum chemical studies of reactivity involve calculations on a large number
of molecular structures and comparison of their energies. Already the set-up of
these calculations limits the scope of the results that one will obtain,
because several system-specific variables such as the charge and spin need to
be set prior to the calculation. For a reliable exploration of reaction
mechanisms, a considerable number of calculations with varying global
parameters must be taken into account, or important facts about the reactivity
of the system under consideration can go undetected. For example, one could
miss crossings of potential energy surfaces for different spin states or might
not note that a molecule is prone to oxidation. Here, we introduce the concept
of molecular propensity to account for the predisposition of a molecular system
to react across different electronic states in certain nuclear configurations.
Within our real-time quantum chemistry framework, we developed an algorithm
that allows us to be alerted to such a propensity of a system under
consideration.


title: Learning a Tree-Structured Ising Model in Order to Make Predictions

abstract:
  We study the problem of learning a tree Ising model from samples such that
subsequent predictions made using the model are accurate. The prediction task
considered in this paper is that of predicting the values of a subset of
variables given values of some other subset of variables. Virtually all
previous work on graphical model learning has focused on recovering the true
underlying graph. We define a distance ("small set TV" or ssTV) between
distributions $P$ and $Q$ by taking the maximum, over all subsets $\mathcal{S}$
of a given size, of the total variation between the marginals of $P$ and $Q$ on
$\mathcal{S}$; this distance captures the accuracy of the prediction task of
interest. We derive non-asymptotic bounds on the number of samples needed to
get a distribution (from the same class) with small ssTV relative to the one
generating the samples. One of the main messages of this paper is that far
fewer samples are needed than for recovering the underlying tree, which means
that accurate predictions are possible using the wrong tree.

categories: math.ST cs.IT math.IT math.PR stat.ML stat.TH


title:
Multi-scale S-fraction reduced-order models for massive wavefield
  simulations

abstract:
  We developed a novel reduced-order multi-scale method for solving large
time-domain wavefield simulation problems. Our algorithm consists of two main
stages. During the first "off-line" stage the fine-grid operator (of the graph
Laplacian type} is partitioned on coarse cells (subdomains). Then
projection-type multi-scale reduced order models (ROMs) are computed for the
coarse cell operators. The off-line stage is embarrassingly parallel as ROM
computations for the subdomains are independent of each other. It also does not
depend on the number of simulated sources (inputs) and it is performed just
once before the entire time-domain simulation. At the second "on-line" stage
the time-domain simulation is performed within the obtained multi-scale ROM
framework. The crucial feature of our formulation is the representation of the
ROMs in terms of matrix Stieltjes continued fractions (S-fractions). The
layered structure of the S-fraction introduces several hidden layers in the ROM
representation, that results in the block-tridiagonal dynamic system within
each coarse cell. This allows us to sparsify the obtained multi-scale subdomain
operator ROMs and to reduce the communications between the adjacent subdomains
which is highly beneficial for a parallel implementation of the on-line stage.
Our approach suits perfectly the high performance computing architectures,
however in this paper we present rather promising numerical results for a
serial computing implementation only. These results include 3D acoustic and
multi-phase anisotropic elastic problems.


title: evt_MNIST: A spike based version of traditional MNIST

abstract:
  Benchmarks and datasets have important role in evaluation of machine learning
algorithms and neural network implementations. Traditional dataset for images
such as MNIST is applied to evaluate efficiency of different training
algorithms in neural networks. This demand is different in Spiking Neural
Networks (SNN) as they require spiking inputs. It is widely believed, in the
biological cortex the timing of spikes is irregular. Poisson distributions
provide adequate descriptions of the irregularity in generating appropriate
spikes. Here, we introduce a spike-based version of MNSIT (handwritten digits
dataset),using Poisson distribution and show the Poissonian property of the
generated streams. We introduce a new version of evt_MNIST which can be used
for neural network evaluation.


title: Solving QBF by Abstraction

abstract:
  Many verification and synthesis approaches rely on solving techniques for
quantified Boolean formulas (QBF). Consequently, solution witnesses, in the
form of Boolean functions, become more and more important as they represent
implementations or counterexamples. We present a recursive counterexample
guided abstraction and refinement algorithm (CEGAR) for solving and certifying
QBFs that exploits structural reasoning on the formula level. The algorithm
decomposes the given QBF into one propositional formula for every block of
quantifiers that abstracts from assignments of variables not bound by this
quantifier block. Further, we show how to derive an efficient certification
extraction method on top of the algorithm. We report on experimental evaluation
of this algorithm in the solver QuAbS (Quantified Abstraction Solver) which won
the most recent QBF competition (QBFEVAL'18). Further, we show the
effectiveness of the certification approach using synthesis benchmarks and a
case study for synthesizing winning strategies in Petri Games.


title:
A note on the multiple-recursive matrix method for generating
  pseudorandom vectors

abstract:
  The multiple-recursive matrix method for generating pseudorandom vectors was
introduced by Niederreiter (Linear Algebra Appl. 192 (1993), 301-328). We
propose an algorithm for finding an efficient primitive multiple-recursive
matrix method. Moreover, for improving the linear complexity, we introduce a
tweak on the contents of the primitive multiple-recursive matrix method.


title:
Direct observation of DNA dynamics in semi-dilute solutions in
  extensional flow

abstract:
  The dynamic behavior of semi-dilute polymer solutions is governed by an
interplay between solvent quality, concentration, molecular weight, and flow
type. Semi-dilute solutions are characterized by large fluctuations in
concentration, wherein polymer coils interpenetrate but may not be
topologically entangled at equilibrium. In non-equilibrium flows, it is
generally thought that polymer chains can self-entangle in semi-dilute
solutions, thereby leading to entanglements in solutions that are nominally
unentangled at equilibrium. Despite recent progress, we still lack a complete
molecular-level understanding of these dynamics. In this work, we use single
molecule techniques to study the dynamics of semi-dilute solutions of DNA in
planar extensional flow, including polymer relaxation from high stretch,
transient stretching dynamics in step-strain experiments, and steady-state
stretching in flow. Our results are consistent with a power-law scaling of the
longest polymer relaxation time in semi-dilute solutions, revealing an
effective excluded volume exponent $\nu$ = 0.56. We further studied the
non-equilibrium stretching dynamics in extensional flow, with results showing a
decrease in transient polymer stretch at moderate Weissenberg number and a
milder coil-to-stretch transition in semi-dilute solutions compared to dilute
solutions. Interestingly, a unique set of molecular conformations during the
transient stretching process for single polymers in semi-dilute solutions is
observed, which suggests transient stretching pathways for polymer chains in
semi-dilute solutions are qualitatively different than dilute solutions due to
intermolecular interactions. Taken together, this work provides a molecular
framework for understanding the non-equilibrium stretching dynamics of
semi-dilute solutions in strong flows.


title: Generalized Palindromic Continued Fractions

abstract:
  In this paper we introduce a generalization of palindromic continued
fractions as studied by Adamczewski and Bugeaud. We refer to these generalized
palindromes as $m$-palindromes, where $m$ ranges over the positive integers. We
provide a simple transcendence criterion for $m$-palindromes, extending and
slightly refining an analogous result of Adamczewski and Bugeaud. We also
provide methods for constructing examples of $m$-palindromes. Such examples
allow us to illustrate our transcendence criterion and to explore the
relationship between $m$-palindromes and stammering continued fractions,
another concept introduced by Adamczewski and Bugeaud.


title:
Confronting Standard Models of Proto--Planetary Disks With New
  Mid--Infrared Sizes from the Keck Interferometer

abstract:
  We present near and mid-infrared interferometric observations made with the
Keck Interferometer Nuller and near-contemporaneous spectro-photometry from the
IRTF of 11 well known young stellar objects, several observed for the first
time in these spectral and spatial resolution regimes. With AU-level spatial
resolution, we first establish characteristic sizes of the infrared emission
using a simple geometrical model consisting of a hot inner rim and mid-infrared
disk emission. We find a high degree of correlation between the stellar
luminosity and the mid-infrared disk sizes after using near-infrared data to
remove the contribution from the inner rim. We then use a semi-analytical
physical model to also find that the very widely used "star + inner dust rim +
flared disk" class of models strongly fails to reproduce the SED and
spatially-resolved mid-infrared data simultaneously; specifically a more
compact source of mid-infrared emission is required than results from the
standard flared disk model. We explore the viability of a modification to the
model whereby a second dust rim containing smaller dust grains is added, and
find that the two-rim model leads to significantly improved fits in most cases.
This complexity is largely missed when carrying out SED modelling alone,
although detailed silicate feature fitting by McClure et al. 2013 recently came
to a similar conclusion. As has been suggested recently by Menu et al. 2015,
the difficulty in predicting mid-infrared sizes from the SED alone might hint
at "transition disk"-like gaps in the inner AU; however, the relatively high
correlation found in our mid-infrared disk size vs. stellar luminosity relation
favors layered disk morphologies and points to missing disk model ingredients
instead.


title:
Neutron capture reactions relevant to s-process and p-process in the
  domain of the $N=50$ shell closure

abstract:
  Radiative thermal neutron capture cross sections for nuclei participating in
s-process and p-process nucleosynthesis in and around $N=50$ closed neutron
shell have been calculated in statistical semi-microscopic Hauser-Feshbach
approach for the energy range of astrophysical interest. A folded optical model
potential is constructed utilizing the standard DDM3Y real nucleon-nucleon
interaction. The folding of the interaction with target radial matter
densities, obtained from the relativistic-mean-field approach, is done in
coordinate space using the spherical approximation. The standard nuclear
reaction code TALYS1.8 is used for cross-section calculation. The cross
sections are compared with experimental results and reasonable agreements are
found for almost all cases. Maxwellian-averaged cross sections (MACS) for the
nuclei are presented at a single thermal energy of 30 keV relevant to
s-process. We have also presented the MACS values over a range of energy from 5
to 100 keV for neutron magic nuclei with $(N=50)$.


title:
A search for evidence of solar rotation in Super-Kamiokande solar
  neutrino dataset

abstract:
  We apply the generalized Lomb-Scargle (LS) periodogram, proposed by
Zechmeister and Kurster, to the solar neutrino data from Super-Kamiokande
(Super-K) using data from its first five years. For each peak in the LS
periodogram, we evaluate the statistical significance in two different ways.
The first method involves calculating the False Alarm Probability (FAP) using
non-parametric bootstrap resampling, and the second method is by calculating
the difference in Bayesian Information Criterion (BIC) between the null
hypothesis, viz. the data contains only noise, compared to the hypothesis that
the data contains a peak at a given frequency. Using these methods, we scan the
frequency range between 7-14 cycles per year to look for any peaks caused by
solar rotation, since this is the proposed explanation for the statistically
significant peaks found by Sturrock and collaborators in the Super-K dataset.
From our analysis, we do confirm that similar to Sturrock et al, the maximum
peak occurs at a frequency of 9.42/year, corresponding to a period of 38.75
days. The FAP for this peak is about 1.5% and the difference in BIC (between
pure white noise and this peak) is about 4.8. We note that the significance
depends on the frequency band used to search for peaks and hence it is
important to use a search band appropriate for solar rotation. However, the
significance of this peak based on the value of BIC is marginal and more data
is needed to confirm if the peak persists and is real.


title:
The rotation-vibration structure of the SO$_2$
  $\mathrm{\tilde{C}}^1\mathrm{B}_2$ state explained by a new internal
  coordinate force field

abstract:
  A new quartic force field for the SO$_2$ $\tilde{\text{C}}$$^1$B$_2$ state
has been derived, based on high resolution data from S$^{16}$O$_2$ and
S$^{18}$O$_2$. Included are eight $b_2$ symmetry vibrational levels of
S$^{16}$O$_2$ reported in the first paper of this series [G. B. Park,
$\textit{et al.}$, J. Chem. Phys. $\textbf{144}$, 144311 (2016)]. Many of the
experimental observables not included in the fit, such as the Franck-Condon
intensities and the Coriolis-perturbed effective $C$ rotational constants of
highly anharmonic $\tilde{\text{C}}$ state vibrational levels, are well
reproduced using our force field. Because the two stretching modes of the
$\tilde{\text{C}}$ state are strongly coupled via Fermi-133 interaction, the
vibrational structure of the $\tilde{\text{C}}$ state is analyzed in a
Fermi-system basis set, constructed explicitly in this work via
$\textit{partial}$ $\textit{diagonalization}$ of the vibrational Hamiltonian.
The physical significance of the Fermi-system basis is discussed in terms of
semiclassical dynamics, based on study of Fermi-resonance systems by Kellman
and coworkers [M. E. Kellman and L. Xiao, J. Chem. Phys. $\textbf{93}$, 5821
(1990)]. By diagonalizing the vibrational Hamiltonian in the Fermi-system
basis, the vibrational characters of all vibrational levels can be determined
unambiguously. It is shown that the bending mode cannot be treated separately
from the coupled stretching modes, particularly at vibrational energies of more
than 2000 cm$^{-1}$. Based on our force field, the structure of the Coriolis
interactions in the $\tilde{\text{C}}$ state of SO$_2$ is also discussed. We
identify the origin of the alternating patterns in the effective $C$ rotational
constants of levels in the vibrational progressions of the symmetry-breaking
mode, $\nu_\beta$ (which correlates with the antisymmetric stretching mode in
our assignment scheme).


title: Cosmological Constraints on Higgs-Dilaton Inflation

abstract:
  We test the viability of the Higgs-dilaton model (HDM) compared to the
evolving dark energy ($w_0 w_a$CDM) model, in which the cosmological constant
model $\Lambda$CDM is also nested, by using the latest cosmological data that
includes the cosmic microwave background temperature, polarization and lensing
data from the \textit{Planck} satellite (2015 data release), the BICEP and Keck
Array experiments, the Type Ia supernovae from the JLA catalog, the baryon
acoustic oscillations from CMASS, LOWZ and 6dF, the weak lensing data from the
CFHTLenS survey and the matter power Spectrum measurements from the SDSS (data
release 7). We find that the values of all cosmological parameters allowed by
the Higgs-dilaton inflation model are well within the \textit{Planck} satellite
(2015 data release) constraints. In particular, we have that $w_0 =
-1.0001^{+0.0072}_{-0.0074}$, $w_a = 0.00^{+0.15}_{-0.16}$, $n_s =
0.9693^{+0.0083}_{-0.0082}$, $\alpha_s = -0.001^{+0.013}_{-0.014}$ and
$r_{0.05} = 0.0025^{+0.0017}_{-0.0016}$ (95.5\%C.L.). We also place new
stringent constraints on the couplings of the Higgs-dilaton model and we find
that $\xi_{\chi} < 0.00328$ and $\xi_h / \sqrt{\lambda} =
59200^{+30000}_{-20000}$ (95.5\%C.L.). Furthermore, we report that the HDM is
at a slightly better footing than the $w_0 w_a$CDM model, as they both have
practically the same chi-square, i.e. $\Delta \chi^2 = \chi^2_{w_0
w_a\mathrm{CDM}}-\chi^2_{\mathrm{HDM}}=0.18$, with the HDM model having two
fewer parameters. Finally Bayesian evidence favors equally the two models, with
the HDM being preferred by the AIC and DIC information criteria.


title:
Nearly constant loss - the 2nd universality of AC conductivity by
  scaling down subsequent random walk steps by 1/t^(1/2)

abstract:
  In the frequency domain, the nearly constant loss, is characterized by a
slope 1 in log of the real part of the electrical conductivity vs log frequency
plots. It can be explained by an anomalous diffusion, defined by a random walk
with the mean square displacement proportional to the logarithm of time, rather
than being linearly proportional to time, as in normal diffusion. The present
work suggests a random walk algorithm that leads to anomalous, logarithmic time
dependence. That has been accomplished by scaling down the subsequent random
walk displacements by a factor, 1/t^(1/2)


title:
Almost Periodic Solutions of Evolution Differential Equations with
  Impulsive Action

abstract:
  In an abstract Banach space we study conditions for the existence of
piecewise continuous, almost periodic solutions for semi-linear impulsive
differential equation with fixed and non-fixed moments of impulsive action


title: Balanced Fair Resource Sharing in Computer Clusters

abstract:
  We represent a computer cluster as a multi-server queue with some arbitrary
bipartite graph of compatibilities between jobs and servers. Each server
processes its jobs sequentially in FCFS order. The service rate of a job at any
given time is the sum of the service rates of all servers processing this job.
We show that the corresponding queue is quasi-reversible and use this property
to design a scheduling algorithm achieving balanced fair sharing of the service
capacity.


title: Quantitative Automata under Probabilistic Semantics

abstract:
  Automata with monitor counters, where the transitions do not depend on
counter values, and nested weighted automata are two expressive
automata-theoretic frameworks for quantitative properties. For a well-studied
and wide class of quantitative functions, we establish that automata with
monitor counters and nested weighted automata are equivalent. We study for the
first time such quantitative automata under probabilistic semantics. We show
that several problems that are undecidable for the classical questions of
emptiness and universality become decidable under the probabilistic semantics.
We present a complete picture of decidability for such automata, and even an
almost-complete picture of computational complexity, for the probabilistic
questions we consider.


title: On Boolean intervals of finite groups

abstract:
  We prove a dual version of {\O}ystein Ore's theorem on distributive intervals
in the subgroup lattice of finite groups, having a nonzero dual Euler totient
$\hat{\varphi}$. For any Boolean group-complemented interval, we observe that
$\hat{\varphi} = \varphi \neq 0$ by the original Ore's theorem. We also discuss
some applications in representation theory. We conjecture that $\hat{\varphi}$
is always nonzero for Boolean intervals. In order to investigate it, we prove
that for any Boolean group-complemented interval $[H,G]$, the graded coset
poset $\hat{P} = \hat{C}(H,G)$ is Cohen-Macaulay and the nontrivial reduced
Betti number of the order complex $\Delta(P)$ is $\hat{\varphi}$, so nonzero.
We deduce that these results are true beyond the group-complemented case with
$|G:H|<32$. One observes that they are also true when $H$ is a Borel subgroup
of $G$.


title: A Novel Approach for Estimating Truck Factors

abstract:
  Truck Factor (TF) is a metric proposed by the agile community as a tool to
identify concentration of knowledge in software development environments. It
states the minimal number of developers that have to be hit by a truck (or
quit) before a project is incapacitated. In other words, TF helps to measure
how prepared is a project to deal with developer turnover. Despite its clear
relevance, few studies explore this metric. Altogether there is no consensus
about how to calculate it, and no supporting evidence backing estimates for
systems in the wild. To mitigate both issues, we propose a novel (and
automated) approach for estimating TF-values, which we execute against a corpus
of 133 popular project in GitHub. We later survey developers as a means to
assess the reliability of our results. Among others, we find that the majority
of our target systems (65%) have TF <= 2. Surveying developers from 67 target
systems provides confidence towards our estimates; in 84% of the valid answers
we collect, developers agree or partially agree that the TF's authors are the
main authors of their systems; in 53% we receive a positive or partially
positive answer regarding our estimated truck factors.


title:
Feedback-induced Bistability of an Optically Levitated Nanoparticle: A
  Fokker-Planck Treatment

abstract:
  Optically levitated nanoparticles have recently emerged as versatile
platforms for investigating macroscopic quantum mechanics and enabling
ultrasensitive metrology. In this article we theoretically consider two damping
regimes of an optically levitated nanoparticle cooled by cavityless parametric
feedback. Our treatment is based on a generalized Fokker-Planck equation
derived from the quantum master equation presented recently and shown to agree
very well with experiment [1]. For low damping, we find that the resulting
Wigner function yields the single-peaked oscillator position distribution and
recovers the appropriate energy distribution derived earlier using a classical
theory and verified experimentally [2]. For high damping, in contrast, we
predict a double-peaked position distribution, which we trace to an underlying
bistability induced by feedback. Unlike in cavity-based optomechanics,
stochastic processes play a major role in determining the bistable behavior. To
support our conclusions, we present analytical expressions as well as numerical
simulations using the truncated Wigner function approach. Our work opens up the
prospect of developing bistability-based devices, characterization of
phase-space dynamics, and investigation of the quantum-classical transition
using levitated nanoparticles.


title:
Evidence for proximity of YFe$_2$Si$_2$ to a magnetic quantum critical
  point

abstract:
  Calculations of the electronic and magnetic properties of the non-magnetic
metallic compound YFe$_2$Si$_2$ are reported. These show that at the density
functional level a magnetic state involving ordering along the $c$-axis. The
electronic structure is three dimensional, and is similar to that of the
unconventional superconductor YFe$_2$Ge$_2$ and as well as that of the high
pressure collapsed tetragonal phase of KFe$_2$As$_2$, which is also a
superconductor. Based on the results in relation to experiment, we infer that
properties of YFe$_2$Si$_2$ are strongly influenced by a nearby
antiferromagnetic quantum critical point.


title: Search for Sterile Neutrinos at Long and Short Baselines

abstract:
  Neutrino physics is currently suffering from lack of knowledge from at least
four major ingredients. One of them is the presence or not of new sterile
neutrino states at the mass scale of around 1 eV. Settling this point should be
the highest priority for the neutrino community. We will discuss the
state-of-the art of experimental searches for sterile neutrinos with
accelerators, both at long and short baselines.


title: A Hybrid Approach to Query Answering under Expressive Datalog+/-

abstract:
  Datalog+/- is a family of ontology languages that combine good computational
properties with high expressive power. Datalog+/- languages are provably able
to capture the most relevant Semantic Web languages. In this paper we consider
the class of weakly-sticky (WS) Datalog+/- programs, which allow for certain
useful forms of joins in rule bodies as well as extending the well-known class
of weakly-acyclic TGDs. So far, only non-deterministic algorithms were known
for answering queries on WS Datalog+/- programs. We present novel deterministic
query answering algorithms under WS Datalog+/-. In particular, we propose: (1)
a bottom-up grounding algorithm based on a query-driven chase, and (2) a hybrid
approach based on transforming a WS program into a so-called sticky one, for
which query rewriting techniques are known. We discuss how our algorithms can
be optimized and effectively applied for query answering in real-world
scenarios.


title:
Irreversibility in physics stemming from unpredictable symbol-handling
  agents

abstract:
  The basic equations of physics involve a time variable t and are invariant
under the transformation $t goes to -t$. This invariance at first sight appears
to impose time reversibility as a principle of physics, in conflict with
thermodynamics. But equations written on the blackboard are not the whole story
in physics. In prior work we sharpened a distinction obscured in today's
theoretical physics, the distinction between obtaining evidence from
experiments on the laboratory bench and explaining that evidence in
mathematical symbols on the blackboard. The sharp distinction rests on a proof
within the mathematics of quantum theory that no amount of evidence,
represented in quantum theory in terms of probabilities, can uniquely determine
its explanation in terms of wave functions and linear operators. Building on
the proof we show here a role in physics for unpredictable symbol-handling
agents acting both at the blackboard and at the workbench, communicating back
and forth by means of transmitted symbols. Because of their unpredictability,
symbol-handling agents introduce a heretofore overlooked source of
irreversibility into physics, even when the equations they write on the
blackboard are invariant under t goes to -t$. Widening the scope of
descriptions admissible to physics to include the agents and the symbols that
link theory to experiments opens up a new source of time-irreversibility in
physics.


title:
Second order differential realization of the Bargmann-Wigner framework
  for particles of any spin

abstract:
  The Bargmann-Wigner (BW) framework describes particles of spin-j in terms of
Dirac spinors of rank 2j, obtained as the local direct product of n Dirac
spinor copies, with n=2j. Such spinors are reducible, and contain also
(j,0)+(0,j)-pure spin representation spaces. The 2(2j+1) degrees of freedom of
the latter are identified by a projector given by the n-fold direct product of
the covariant parity projector within the Dirac spinor space. Considering
totally symmetric tensor spinors one is left with the expected number of
2(2j+1) independent degrees of freedom. The BW projector is of the order
$\partial ^{2j}$ in the derivatives, and so are the related spin-j wave
equations and associated Lagrangians. High order differential equations can not
be consistently gauged, and allow several unphysical aspects, such as
non-locality, acausality, ghosts and etc to enter the theory. In order to avoid
these difficulties we here suggest a strategy of replacing the high order of
the BW wave equations by the universal second order. To do so we replaced the
BW projector by one of zeroth order in the derivatives. We built it up from one
of the Casimir invariants of the Lorentz group when exclusively acting on
spaces of internal spin degrees of freedom. This projector allows one to
identify anyone of the irreducible sectors of the primordial rank-2j spinor, in
particular (j,0)+(0,j), and without any reference to the external space-time
and the four-momentum. The dynamics is then introduced by requiring the (j,0)+
(0,j) sector to satisfy the Klein-Gordon equation. The scheme allows for a
consistent minimal gauging.


title: The infinite turn and speculative explanations in cosmology

abstract:
  Infinity, in various guises, has been invoked recently in order to `explain'
a number of important questions regarding observable phenomena in science, and
in particular in cosmology. Such explanations are by their nature speculative.
Here we introduce the notions of relative infinity, closure, and economy of
explanation and ask: to what extent explanations involving relative or real
constructed infinities can be treated as reasonable?

categories: physics.hist-ph astro-ph.CO gr-qc hep-ph


title: A proposal to classify the radian as a base unit in the SI

abstract:
  We propose that the SI be modified so that the radian is a base unit. Some of
the details and consequences of such a modification are examined.


title:
Spooky Action at No Distance: On the individuation of quantum mechanical
  systems

abstract:
  Recent experiments have perfectly verified the fact that quantum correlations
between two entangled particles are stronger than any classical, local
pre-quantum worldview allows. This is famously called the EPR paradox first
conceived as a thought experiment and decades later realized in the lab. We
discuss in depth the nature of the paradox and show that the problematics it
presents is first and foremost epistemological. After briefly exploring
resolutions to the paradox that after many decades of discourse still remain
controversial, we argue that the paradox is rooted in the failure of our
current metaphysical scheme, being the foundation of our knowledge, to
accommodate and cohere our knowledge of the phenomena of entanglement. We then
develop and make the case for a novel and more fundamental resolution of the
paradox by changing the underlying metaphysical foundation from one based on
individuals to a one based on individuation. We discuss in detail how in the
light of this new scheme concepts central to the paradox such as realism,
causality and locality are adjusted to the effect that the paradox is resolved
without giving up these concepts so fundamental to our thinking. We conclude
with a brief note about the important role of metaphysics to the progress of
knowledge and our understanding of reality.


title: Yet another symmetry breaking to be discovered

abstract:
  The discovery of spontaneous symmetry breaking in particle physics was the
greatest contribution in Nambu's achievements. There is another class of
symmetries that exist in the low energy nature, yet is doomed to be broken at
high energy, due to a lack of protection of the gauge symmetry. I shall review
our approach to search for this class of symmetry breaking, the lepton number
violation linked to generation of the matter-antimatter asymmetry in our
universe.


title:
Global Sensitivity Analysis with 2D Hydraulic Codes: Application on
  Uncertainties Related to High-Resolution Topographic Data

abstract:
  Technologies such as aerial photogrammetry allow production of 3D topographic
data including complex environments such as urban areas. Therefore, it is
possible to create High Resolution (HR) Digital Elevation Models (DEM)
incorporating thin above ground elements influencing overland flow paths. Even
though this category of big data has a high level of accuracy, there are still
errors in measurements and hypothesis under DEM elaboration. Moreover,
operators look for optimizing spatial discretization resolution in order to
improve flood models computation time. Errors in measurement, errors in DEM
generation, and operator choices for inclusion of this data within 2D hydraulic
model, might influence results of flood models simulations. These errors and
hypothesis may influence significantly flood modelling results variability. The
purpose of this study is to investigate uncertainties related to (i) the own
error of high resolution topographic data, and (ii) the modeller choices when
including topographic data in hydraulic codes. The aim is to perform a Global
Sensitivity Analysis (GSA) which goes through a Monte-Carlo uncertainty
propagation, to quantify impact of uncertainties, followed by a Sobol' indices
computation, to rank influence of identified parameters on result variability.
A process using a coupling of an environment for parametric computation
(Prom{\'e}th{\'e}e) and a code relying on 2D shallow water equations (FullSWOF
2D) has been developed (P-FS tool). The study has been performed over the lower
part of the Var river valley using the estimated hydrograph of 1994 flood
event. HR topographic data has been made available for the study area, which is
17.5 km 2 , by Nice municipality. Three uncertain parameters were studied: the
measurement error (var. E), the level of details of above-ground element
representation in DEM (buildings, sidewalks, etc.) (var. S), and the spatial
discretization resolution (grid cell size for regular mesh) (var. R). Parameter
var. E follows a probability density function, whereas parameters var. S and
var. R. are discrete operator choices. Combining these parameters, a database
of 2, 000 simulations has been produced using P-FS tool implemented on a high
performance computing structure. In our study case, the output of interest is
the maximal


title: Benchmarking Deep Reinforcement Learning for Continuous Control

abstract:
  Recently, researchers have made significant progress combining the advances
in deep learning for learning feature representations with reinforcement
learning. Some notable examples include training agents to play Atari games
based on raw pixel data and to acquire advanced manipulation skills using raw
sensory inputs. However, it has been difficult to quantify progress in the
domain of continuous control due to the lack of a commonly adopted benchmark.
In this work, we present a benchmark suite of continuous control tasks,
including classic tasks like cart-pole swing-up, tasks with very high state and
action dimensionality such as 3D humanoid locomotion, tasks with partial
observations, and tasks with hierarchical structure. We report novel findings
based on the systematic evaluation of a range of implemented reinforcement
learning algorithms. Both the benchmark and reference implementations are
released at https://github.com/rllab/rllab in order to facilitate experimental
reproducibility and to encourage adoption by other researchers.