title: Kepler Transit Depths Contaminated by a Phantom Star

abstract:
  We present ground-based observations from the Discovery Channel Telescope
(DCT) of three transits of Kepler-445c---a supposed super-Earth exoplanet with
properties resembling GJ 1214b---and demonstrate that the transit depth is
approximately 50 percent shallower than the depth previously inferred from
Kepler Spacecraft data. The resulting decrease in planetary radius
significantly alters the interpretation of the exoplanet's bulk composition.
Despite the faintness of the M4 dwarf host star, our ground-based photometry
clearly recovers each transit and achieves repeatable 1-sigma precision of
approximately 0.2 percent (2 millimags). The transit parameters estimated from
the DCT data are discrepant with those inferred from the Kepler data to at
least 17-sigma confidence. This inconsistency is due to a subtle miscalculation
of the stellar crowding metric during the Kepler pre-search data conditioning
(PDC). The crowding metric, or CROWDSAP, is contaminated by a non-existent
"phantom star" originating in the USNO-B1 catalog and inherited by the Kepler
Input Catalog (KIC). Phantom stars in the KIC are likely rare, but they have
the potential to affect statistical studies of Kepler targets that use the PDC
transit depths for a large number of exoplanets where individual follow-up
observation of each is not possible. The miscalculation of Kepler-445c's
transit depth emphasizes the importance of stellar crowding in the Kepler data,
and provides a cautionary tale for the analysis of data from the Transiting
Exoplanet Survey Satellite (TESS), which will have even larger pixels than
Kepler.


title:
Chromospherically Active Stars in the RAVE Survey. II. Young dwarfs in
  the Solar neighborhood

abstract:
  A large sample of over 38,000 chromospherically active candidate solar-like
stars and cooler dwarfs from the RAVE survey is addressed in this paper. An
improved activity identification with respect to the previous study was
introduced to build a catalog of field stars in the Solar neighborhood with an
excess emission flux in the calcium infrared triplet wavelength region. The
central result of this work is the calibration of the age--activity relation
for the main sequence dwarfs in a range from a few $10 \; \mathrm{Myr}$ up to a
few Gyr. It enabled an order of magnitude age estimation of the entire active
sample. Almost 15,000 stars are shown to be younger than $1\;\mathrm{Gyr}$ and
$\sim$2000 younger than $100\;\mathrm{Myr}$. The young age of the most active
stars is confirmed by their position off the main sequence in the $J-K$ versus
$N_{UV}-V$ diagram showing strong ultraviolet excess, mid-infrared excess in
the $J-K$ versus $W_1-W_2$ diagram and very cool temperatures ($J-K>0.7$). They
overlap with the reference pre-main sequence RAVE stars often displaying X-ray
emission. The activity level increasing with the color reveals their different
nature from the solar-like stars and probably represents an underlying dynamo
generating magnetic fields in cool stars. 50\% of the RAVE objects from DR5 are
found in the TGAS catalog and supplemented with accurate parallaxes and proper
motions by Gaia. This makes the database of a large number of young stars in a
combination with RAVE's radial velocities directly useful as a tracer of the
very recent large-scale star formation history in the Solar neighborhood. The
data are available online in the Vizier database.


title: Scrambling and thermalization in a diffusive quantum many-body system

abstract:
  Out-of-time ordered (OTO) correlation functions describe scrambling of
information in correlated quantum matter. They are of particular interest in
incoherent quantum systems lacking well defined quasi-particles. Thus far, it
is largely elusive how OTO correlators spread in incoherent systems with
diffusive transport governed by a few globally conserved quantities. Here, we
study the dynamical response of such a system using high-performance
matrix-product-operator techniques. Specifically, we consider the
non-integrable, one-dimensional Bose-Hubbard model in the incoherent
high-temperature regime. Our system exhibits diffusive dynamics in time-ordered
correlators of globally conserved quantities, whereas OTO correlators display a
ballistic, light-cone spreading of quantum information. The slowest process in
the global thermalization of the system is thus diffusive, yet information
spreading is not inhibited by such slow dynamics. We furthermore develop an
experimentally feasible protocol to overcome some challenges faced by existing
proposals and to probe time-ordered and OTO correlation functions. Our study
opens new avenues for both the theoretical and experimental exploration of
thermalization and information scrambling dynamics.

categories: cond-mat.quant-gas cond-mat.stat-mech hep-th quant-ph


title:
Impact of $(\alpha,n)$ reactions on weak r-process in neutrino-driven
  winds

abstract:
  After a successful core-collapse supernova, a neutrino-driven wind develops
where it is possible to synthesize lighter heavy elements ($30<Z<45$). In the
early galaxy, the origin of these elements is associated to the r-process and
to an additional process. Here we assume the additional process corresponds to
the weak r-process or alpha-process taking place in neutrino-driven winds.
Based on a trajectory obtained from hydrodynamical simulations we study the
astrophysics and nuclear physics uncertainties with our main focus on the
$(\alpha,n)$ reactions. These are critical to redistribute the matter and allow
to further move it from light to heavy elements after nuclear statistical
equilibrium freezes out. In this first sensitivity study, we vary all
$(\alpha,n)$ reactions by given constant factors which are justified based on
the uncertainties of the statistical model and its nuclear physics input,
mainly alpha optical potentials under the conditions found in the wind. Our
results show that $(\alpha,n)$ reactions are indeed very important to predict
abundances. Therefore, further studies will follow to identify individual
critical reactions. Since the nucleosynthesis path is close to stability, these
reactions can be measured in the near future. This will uniquely allow to
reduce the nuclear physics uncertainties and thus to use observations to
constrain and understand the astrophysical conditions in the wind.


title: Non-gaussianity of the critical 3d Ising model

abstract:
  We discuss the 4pt function of the critical 3d Ising model, extracted from
recent conformal bootstrap results. We focus on the non-gaussianity Q - the
ratio of the 4pt function to its gaussian part given by three Wick
contractions. This ratio reveals significant non-gaussianity of the critical
fluctuations. The bootstrap results are consistent with a rigorous inequality
due to Lebowitz and Aizenman, which limits Q to lie between 1/3 and 1.

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


title: Multi-partite entanglement

abstract:
  We give an introduction to the theory of multi-partite entanglement. We begin
by describing the "coordinate system" of the field: Are we dealing with pure or
mixed states, with single or multiple copies, what notion of "locality" is
being used, do we aim to classify states according to their "type of
entanglement" or to quantify it? Building on the general theory of
multi-partite entanglement - to the extent that it has been achieved - we turn
to explaining important classes of multi-partite entangled states, including
matrix product states, stabilizer and graph states, bosonic and fermionic
Gaussian states, addressing applications in condensed matter theory. We end
with a brief discussion of various applications that rely on multi-partite
entangled states: quantum networks, measurement-based quantum computing,
non-locality, and quantum metrology.


title: Hunting the Gluon Orbital Angular Momentum at the Electron-Ion Collider

abstract:
  Applying the connection between the parton Wigner distribution and orbital
angular momentum (OAM), we investigate the probe of the gluon OAM in hard
scattering processes at the planned electron-ion collider. We show that the
single longitudinal target-spin asymmetry in the hard diffractive dijet
production is very sensitive to the gluon OAM distribution. The associated spin
asymmetry leads to a characteristic azimuthal angular correlation of
$\sin(\phi_q -\phi_\Delta)$, where $\phi_\Delta$ and $\phi_q$ are the azimuthal
angles of the proton momentum transfer and the relative transverse momentum
between the quark-antiquark pair. This study will enable a first measurement of
the gluon OAM in the proton spin sum rule.


title: Magnetoresistance of compensated semimetals in confined geometries

abstract:
  Two-component conductors -- e.g., semi-metals and narrow band semiconductors
-- often exhibit unusually strong magnetoresistance in a wide temperature
range. Suppression of the Hall voltage near charge neutrality in such systems
gives rise to a strong quasiparticle drift in the direction perpendicular to
the electric current and magnetic field. This drift is responsible for a strong
geometrical increase of resistance even in weak magnetic fields. Combining the
Boltzmann kinetic equation with sample electrostatics, we develop a microscopic
theory of magnetotransport in two and three spatial dimensions. The compensated
Hall effect in confined geometry is always accompanied by electron-hole
recombination near the sample edges and at large-scale inhomogeneities. As the
result, classical edge currents may dominate the resistance in the vicinity of
charge compensation. The effect leads to linear magnetoresistance in two
dimensions in a broad range of parameters. In three dimensions, the
magnetoresistance is normally quadratic in the field, with the linear regime
restricted to rectangular samples with magnetic field directed perpendicular to
the sample surface. Finally, we discuss the effects of heat flow and
temperature inhomogeneities on the magnetoresistance.

categories: cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.stat-mech cond-mat.str-el


title:
Comoving stars in Gaia DR1: An abundance of very wide separation
  co-moving pairs

abstract:
  The primary sample of the {\it Gaia} Data Release 1 is the Tycho-Gaia
Astrometric Solution (TGAS): $\approx$ 2 million Tycho-2 sources with improved
parallaxes and proper motions relative to the initial catalog. This increased
astrometric precision presents an opportunity to find new binary stars and
moving groups. We search for high-confidence comoving pairs of stars in TGAS by
identifying pairs of stars consistent with having the same 3D velocity using a
marginalized likelihood ratio test to discriminate candidate comoving pairs
from the field population. Although we perform some visualizations using (bias-
corrected) inverse parallax as a point estimate of distance, the likelihood
ratio is computed with a probabilistic model that includes the covariances of
parallax and proper motions and marginalizes the (unknown) true distances and
3D velocities of the stars. We find 13,085 comoving star pairs among 10,606
unique stars with separations as large as 10 pc (our search limit). Some of
these pairs form larger groups through mutual comoving neighbors: many of these
pair networks correspond to known open clusters and OB associations, but we
also report the discovery of several new comoving groups. Most surprisingly, we
find a large number of very wide ($>1$ pc) separation comoving star pairs, the
number of which increases with increasing separation and cannot be explained
purely by false-positive contamination. Our key result is a catalog of
high-confidence comoving pairs of stars in TGAS. We discuss the utility of this
catalog for making dynamical inferences about the Galaxy, testing stellar
atmosphere models, and validating chemical abundance measurements.


title: Absolute dimensions of the eccentric eclipsing binary V541 Cygni

abstract:
  We report new spectroscopic and photometric observations of the
main-sequence, detached, eccentric, double-lined eclipsing binary V541 Cyg (P =
15.34 days, e = 0.468). Using these observations together with existing
measurements we determine the component masses and radii to better than 1%
precision: M1 = 2.335 +0.017/-0.013 MSun, M2 = 2.260 +0.016/-0.013 MSun, R1 =
1.859 +0.012/-0.009 RSun, and R2 = 1.808 +0.015/-0.013 RSun. The nearly
identical B9.5 stars have estimated temperatures of 10650 +/- 200 K and 10350
+/- 200 K. A comparison of these properties with current stellar evolution
models shows excellent agreement at an age of about 190 Myr and [Fe/H]
approximately -0.18. Both components are found to be rotating at the
pseudo-synchronous rate. The system displays a slow periastron advance that is
dominated by General Relativity (GR), and has previously been claimed to be
slower than predicted by theory. Our new measurement, dw/dt = 0.859
+0.042/-0.017 deg/century, has an 88% contribution from GR and agrees with the
expected rate within the uncertainties. We also clarify the use of the gravity
darkening coefficients in the light-curve fitting program EBOP, a version of
which we use here.


title:
Fast State Transfer and Entanglement Renormalization Using Long-Range
  Interactions

abstract:
  In short-range interacting systems, the speed at which entanglement can be
established between two separated points is limited by a constant Lieb-Robinson
velocity. Long-range interacting systems are capable of faster entanglement
generation, but the degree of the speed-up possible is an open question. In
this paper, we present a protocol capable of transferring a quantum state
across a distance $L$ in $d$ dimensions using long-range interactions with
strength bounded by $1/r^\alpha$. If $\alpha < d$, the state transfer time is
asymptotically independent of $L$; if $\alpha = d$, the time is logarithmic in
distance $L$; if $d < \alpha < d+1$, transfer occurs in time proportional to
$L^{\alpha - d}$; and if $\alpha \geq d + 1$, it occurs in time proportional to
$L$. We then use this protocol to upper bound the time required to create a
state specified by a MERA (multiscale entanglement renormalization ansatz)
tensor network, and show that, if the linear size of the MERA state is $L$,
then it can be created in time that scales with $L$ identically to state
transfer up to multiplicative logarithmic corrections.


title: Binaries among low-mass stars in nearby young moving groups

abstract:
  The solar galactic neighbourhood contains a number of young co-moving
associations of stars (so-called `young moving groups') with ages of ~10--150
Myr, which are prime targets for a range of scientific studies, including
direct imaging planet searches. The late-type stellar population of such groups
still remain in their pre-main sequence phase, and are thus well suited for
purposes such as isochronal dating. Close binaries are particularly useful in
this regard, since they allow for a model-independent dynamical mass
determination. Here we present a dedicated effort to identify new close
binaries in nearby young moving groups, through high-resolution imaging with
the AstraLux Sur Lucky Imaging camera. We surveyed 181 targets, resulting in
the detection of 61 companions or candidates, of which 38 are new discoveries.
An interesting example of such a case is 2MASS J00302572-6236015 AB, which is a
high-probability member of the Tucana-Horologium moving group, and has an
estimated orbital period of less than 10 years. Among the previously known
objects is a serendipitous detection of the deuterium burning boundary
circumbinary companion 2MASS J01033563-5515561 (AB)b in the z'-band, thereby
extending the spectral coverage for this object down to near-visible
wavelengths.


title:
Hybrid continuous and periodic barrier strategies in the dual model:
  optimality and fluctuation identities

abstract:
  Avanzi et al. (2016) recently studied an optimal dividend problem where
dividends are paid both periodically and continuously with different
transaction costs. In the Brownian model with Poissonian periodic dividend
payment opportunities, they showed that the optimal strategy is either of the
pure-continuous, pure-periodic, or hybrid-barrier type. In this paper, we
generalize the results of their previous study to the dual (spectrally positive
L\'evy) model. The optimal strategy is again of the hybrid-barrier type and can
be concisely expressed using the scale function. These results are confirmed
through a sequence of numerical experiments.


title: Gluon orbital angular momentum at small-$x$

abstract:
  We present a general analysis of the orbital angular momentum (OAM)
distribution of gluons $L_g(x)$ inside the nucleon with particular emphasis on
the small-$x$ region. We derive a novel operator representation of $L_g(x)$ in
terms of Wilson lines and argue that it is approximately proportional to the
gluon helicity distribution $L_g(x) \approx -2\Delta G(x)$ at small-$x$. We
also compute longitudinal single spin asymmetry in exclusive diffractive dijet
production in lepton-nucleon scattering in the next-to-eikonal approximation
and show that the asymmetry is a direct probe of the gluon helicity/OAM
distribution as well as the QCD odderon exchange.


title:
Analysis of Ground Level Enhancements (GLE): Extreme solar energetic
  particle events have hard spectra

abstract:
  Nearly 70 Ground Level Enhancements (GLEs) of cosmic rays have been recorded
by the worldwide neutron monitor network since the 1950s depicting a big
variety of energy spectra of solar energetic particles (SEP). Here we studied a
statistical relation between the event-integrated intensity of GLEs (calculated
as count-rate relative excess, averaged over all available polar neutron
monitors, and expressed in percent-hours) and the hardness of the solar
particle energy spectra. For each event the integral omnidirectional
event-integrated fluences of particles with energy above 30 MeV ($F_{30}$) and
above 200 MeV ($F_{200}$) were computed using the reconstructed spectra, and
the ratio between the two fluences was considered as a simple index of the
event's hardness. We also provided a justification of the spectrum estimate in
the form of the Band-function, using direct PAMELA data for GLE 71
(17-May-2012). We found that, while there is no clear relation between the
intensity and the hardness for weak events, all strong events with the
intensity greater 100 \%*hr are characterized by a very hard spectrum. This
implies that a hard spectrum can be securely assumed for all extreme GLE
events, e.g., those studied using cosmogenic isotope data in the past.


title: Cosmological evolution of Yukawa couplings: the 5D perspective

abstract:
  The cosmological evolution of standard model Yukawa couplings may have major
implications for baryogenesis. In particular, as highlighted recently, the CKM
matrix alone could be the source of CP-violation during electroweak
baryogenesis provided that the Yukawa couplings were large and varied during
the electroweak phase transition. We provide a natural realisation of this idea
in the context of Randall-Sundrum models and show that the geometrical warped
approach to the fermion mass hierarchy may naturally display the desired
cosmological dynamics. The key ingredient is the coupling of the
Goldberger-Wise scalar, responsible for the IR brane stabilisation, to the bulk
fermions, which modifies the fermionic profiles. This also helps alleviating
the usually tight constraints from CP-violation in Randall-Sundrum scenarios.
We study how the Yukawa couplings vary during the stabilisation of the
Randall-Sundrum geometry and can thus induce large CP-violation during the
electroweak phase transition. Using holography, we discuss the 4D
interpretation of this dynamical interplay between flavour and electroweak
symmetry breaking.


title: Coined Quantum Walks as Quantum Markov Chains

abstract:
  We analyze the equivalence between discrete-time coined quantum walks and
Szegedy's quantum walks. We characterize a class of flip-flop coined models
with generalized Grover coin on a graph $\Gamma$ that can be directly converted
into Szegedy's model on the subdivision graph of $\Gamma$ and we describe a
method to convert one model into the other. This method improves previous
results in literature that need to use the staggered model and the concept of
line graph, which are avoided here.


title:
Cosmological constant vis-a-vis dynamical vacuum: bold challenging the
  $\Lambda$CDM

abstract:
  Next year we will celebrate 100 years of the cosmological term, $\Lambda$, in
Einstein's gravitational field equations, also 50 years since the cosmological
constant problem was first formulated by Zeldovich, and almost about two
decades of the observational evidence that a non-vanishing, positive,
$\Lambda$-term could be the simplest phenomenological explanation for the
observed acceleration of the Universe. This mixed state of affairs already
shows that we do no currently understand the theoretical nature of $\Lambda$.
In particular, we are still facing the crucial question whether $\Lambda$ is
truly a fundamental constant or a mildly evolving dynamical variable. At this
point the matter should be settled once more empirically and, amazingly enough,
the wealth of observational data at our disposal can presently shed true light
on it. In this short review I summarize the situation of some of these studies.
It turns out that the $\Lambda=$const. hypothesis, despite being the simplest,
may well not be the most favored one when we put it in hard-fought competition
with specific dynamical models of the vacuum energy. Recently it has been shown
that the overall fit to the cosmological observables
$SNIa+BAO+H(z)+LSS+BBN+CMB$ do favor the class of "running" vacuum models
(RVM's) -- in which $\Lambda=\Lambda(H)$ is a function of the Hubble rate --
against the "concordance" $\Lambda$CDM model. The support is at an
unprecedented level of $\sim4\sigma$ and is backed up with Akaike and Bayesian
criteria leading to compelling evidence in favor of the RVM option and other
related dynamical vacuum models. I also address the implications of this
framework on the possible time evolution of the fundamental constants of
Nature.


title:
Wellposedness of Neumann boundary-value problems of space-fractional
  differential equations

abstract:
  Fractional differential equation (FDE) provides an accurate description of
transport processes that exhibit anomalous diffusion but introduces new
mathematical difficulties that have not been encountered in the context of
integer-order differential equation. For example, the wellposedness of the
Dirichlet boundary-value problem of one-dimensional variable-coefficient FDE is
not fully resolved yet. In addition, Neumann boundary-value problem of FDE
poses significant challenges, partly due to the fact that different forms of
FDE and different types of Neumann boundary condition have been proposed in the
literature depending on different applications.
  We conduct preliminary mathematical analysis of the wellposedness of
different Neumann boundary-value problems of the FDEs. We prove that five out
of the nine combinations of three different forms of FDEs that are closed by
three types of Neumann boundary conditions are well posed and the remaining
four do not admit a solution. In particular, for each form of the FDE there is
at least one type of Neumann boundary condition such that the corresponding
boundary-value problem is well posed, but there is also at least one type of
Neumann boundary condition such that the corresponding boundary-value problem
is ill posed. This fully demonstrates the subtlety of the study of FDE.


title: Perfect Transmission through Disordered Media

abstract:
  The transmission of a wave through a randomly chosen `pile of plates'
typically decreases exponentially with the number of plates, a phenomenon
closely related to Anderson localisation. In apparent contradiction we
construct disordered planar permittivity profiles which are complex-valued
(i.e. have reactive and dissipative properties) that appear to vary randomly
with position, yet are one-way reflectionless for all angles of incidence and
exhibit a transmission coefficient of unity. We contrast these complex-valued
'random' planar permittivity profiles with a family of real-valued, two-way
reflectionless and perfectly transmitting disordered permittivity profiles that
function only for a single angle of incidence and frequency.


title:
Asymptotic safety in three-dimensional SU(2) Group Field Theory:
  evidence in the local potential approximation

abstract:
  We study the functional renormalization group of a three-dimensional
tensorial Group Field Theory (GFT) with gauge group SU(2). This model generates
(generalized) lattice gauge theory amplitudes, and is known to be
perturbatively renormalizable up to order 6 melonic interactions. We consider a
series of truncations of the exact Wetterich--Morris equation, which retain
increasingly many perturbatively irrelevant melonic interactions. This
tensorial analogue of the ordinary local potential approximation allows to
investigate the existence of non-perturbative fixed points of the
renormalization group flow. Our main finding is a candidate ultraviolet fixed
point, whose qualitative features are reproduced in all the truncations we have
checked (with up to order 12 interactions). This may be taken as evidence for
an ultraviolet completion of this GFT in the sense of asymptotic safety.
Moreover, this fixed point has a single relevant direction, which suggests the
presence of two distinct infrared phases. Our results generally support the
existence of GFT phases of the condensate type, which have recently been
conjectured and applied to quantum cosmology and black holes.


title:
Effect of anisotropy on generalized Chaplygin gas scalar field and its
  interaction with other dark energy models

abstract:
  In this work, we establish a correspondence between the interacting
holographic, new agegraphic dark energy and generalized Chaplygin gas model in
Bianchi type I universe. In continue, we reconstruct the potential of the
scalar field which describes the generalized Chaplygin cosmology. Cosmological
solutions are obtained when the kinetic energy of the phantom field is order of
the anisotropy and dominates over the potential energy of the field. We
investigate observational constraints on the generalized Chaplygin gas,
holographic and new agegraphic dark energy models as the unification of dark
matter and dark energy, by using the latest observational data. To do this we
focus on observational determinations of the expansion history $H(z)$. It is
shown that the HDE model is better than the NADE and generalized Chaplygin gas
models in an anisotropic universe. Then, we calculate the evolution of density
perturbations in the linear regime for three models of dark energy and compare
the results $\Lambda$CDM model. Finally, the analysis shows that the increase
in anisotropy leads to more correspondence between the dark energy scalar field
model and observational data


title: Separate Universes beyond General Relativity

abstract:
  We establish purely geometric or metric-based criteria for the validity of
the separate universe ansatz, under which the evolution of small-scale
observables in a long-wavelength perturbation is indistinguishable from a
separate Friedmann-Robertson-Walker cosmology in their angle average. In order
to be able to identify the local volume expansion and curvature in a
long-wavelength perturbation with those of the separate universe, we show that
the lapse perturbation must be much smaller in amplitude than the curvature
potential on a time slicing that comoves with the Einstein tensor. Interpreting
the Einstein tensor as an effective stress energy tensor, the condition is that
the effective stress energy comoves with freely falling synchronous observers
who establish the local expansion, so that the local curvature is conserved. By
matching the expansion history of these synchronous observers in cosmological
simulations, one can establish and test consistency relations even in the
nonlinear regime of modified gravity theories.


title: Relativistic Algebra of Space-Time and Algebrodynamics

abstract:
  We consider a manifestly Lorentz invariant form $\mathbb L$ of the
biquaternion algebra and its generalization to the case of curved manifold. The
conditions of $\mathbb L$-differentiability of $\mathbb L$-functions are
formulated and considered as the primary equations for fundamental fields
modeled with such functions. The exact form of the effective affine connection
induced by $\mathbb L$-differentiability equations is obtained for the flat and
curved cases. In the flat case, the integrability conditions of the latter lead
to the self-duality of the corresponding curvature, thus ensuring that the
source-free Maxwell and $SL(2,\mathbb C)$ Yang-Mills equations hold on the
solutions of the $\mathbb L$-differentiability equations


title:
Relational evolution of effectively interacting GFT quantum gravity
  condensates

abstract:
  We study the impact of effective interactions onto relationally evolving GFT
condensates based on real-valued fields. In a first step we show that a free
condensate configuration in an isotropic restriction settles dynamically into a
low-spin configuration of the quantum geometry. This goes hand in hand with the
accelerated and exponential expansion of its volume, as well as the vanishing
of its relative uncertainty which suggests the classicalization of the quantum
geometry. The dynamics of the emergent space can then be given in terms of the
classical Friedmann equations. In contrast to models based on complex-valued
fields, solutions avoiding the singularity problem can only be found if the
initial conditions are appropriately chosen. We then turn to the analysis of
the influence of effective interactions on the dynamics by studying in
particular the Thomas-Fermi regime. In this context, at the cost of
fine-tuning, an epoch of inflationary expansion of quantum geometric origin can
be implemented. Finally, and for the first time, we study anisotropic GFT
condensate configurations and show that such systems tend to isotropize quickly
as the value of the relational clock grows. This paves the way to a more
systematic investigation of anisotropies in the context of GFT condensate
cosmology.


title:
Quelques contributions \`a la th\'eorie de l'action de SL(2,R) sur les
  espaces de modules de surfaces plates

abstract:
  This memoir is part of the author's `Habilitation \`a Diriger des Recherches'
(HDR) dossier: it summarizes some of his researches after his PhD thesis.
  (The HDR diploma is general requirement for many purposes [e.g., supervising
PhD students] within the French academic system.)


title: Constant curvature factorable surfaces in 3-dimensional isotropic space

abstract:
  In this paper, we study factorable surfaces in a 3-dimensional isotropic
space. We classify such surfaces with constant isotropic Gaussian (K) and mean
curvature (H). We provide a non-existence result related with the surfaces
satisfying H/K=const. Several examples are also illustrated.


title: Reflecting at the Speed of Light

abstract:
  A perfectly reflecting accelerating boundary produces thermal emission to an
observer at $\mathscr{I}_L^+$ and a finite amount of energy to an observer at
$\mathscr{I}_R^+$ by asymptotically traveling to the speed of light without an
acceleration horizon.


title: Demographical Priors for Health Conditions Diagnosis Using Medicare Data

abstract:
  This paper presents an example of how demographical characteristics of
patients influence their susceptibility to certain medical conditions. In this
paper, we investigate the association of health conditions to age of patients
in a heterogeneous population. We show that besides the symptoms a patients is
having, the age has the potential of aiding the diagnostic process in
hospitals. Working with Electronic Health Records (EHR), we show that medical
conditions group into clusters that share distinctive population age densities.
We use Electronic Health Records from Brazil for a period of 15 months from
March of 2013 to July of 2014. The number of patients in the data is 1.7
million patients and the number of records is 47 million records. The findings
has the potential of helping in a setting where an automated system undergoes
the task of predicting the condition of a patient given their symptoms and
demographical information.


title: Discrete Reifenberg-type theorem

abstract:
  The paper proves that a bound on the averaged Jones' square function of a
measure implies an upper bound on the measure. Various types of assumptions on
the measure are considered. The theorem is a generalization of a result due to
A. Naber and D. Valtorta in connection with measure bounds on the singular set
of harmonic maps.


title: Normalisation by Evaluation for Type Theory, in Type Theory

abstract:
  We develop normalisation by evaluation (NBE) for dependent types based on
presheaf categories. Our construction is formulated in the metalanguage of type
theory using quotient inductive types. We use a typed presentation hence there
are no preterms or realizers in our construction, and every construction
respects the conversion relation. NBE for simple types uses a logical relation
between the syntax and the presheaf interpretation. In our construction, we
merge the presheaf interpretation and the logical relation into a
proof-relevant logical predicate. We prove normalisation, completeness,
stability and decidability of definitional equality. Most of the constructions
were formalized in Agda.


title: Community detection by label propagation with compression of flow

abstract:
  The label propagation algorithm (LPA) has been proved to be a fast and
effective method for detecting communities in large complex networks. However,
its performance is subject to the non-stable and trivial solutions of the
problem. In this paper, we propose a modified label propagation algorithm LPAf
to efficiently detect community structures in networks. Instead of the majority
voting rule of the basic LPA, LPAf updates the label of a node by considering
the compression of a description of random walks on a network. A multi-step
greedy agglomerative strategy is employed to enable LPAf to escape the local
optimum. Furthermore, an incomplete update condition is also adopted to speed
up the convergence. Experimental results on both synthetic and real-world
networks confirm the effectiveness of our algorithm.


title: Positive speed self-avoiding walks on graphs with more than one end

abstract:
  A self-avoiding walk (SAW) is a path on a graph that visits each vertex at
most once. The mean square displacement of an $n$-step SAW is the expected
value of the square of the distance between the ending point and the starting
point of an $n$-step SAW, where the expectation is taken with respect to the
uniform measure on $n$-step SAWs starting from a fixed vertex. It is
conjectured that the mean square displacement of an $n$-step SAW is
asymptotically $n^{2\nu}$, where $\nu$ is a constant. Computing the exact
values of the exponent $\nu$ on various graphs has been a challenging problem
in mathematical and scientific research for long.
  In this paper we show that on any locally finite Cayley graph of an infinite,
finitely-generated group with more than two ends, the number of SAWs whose
end-to-end distances are linear in lengths has the same exponential growth rate
as the number of all the SAWs. We also prove that for any infinite,
finitely-generated group with more than one end, there exists a locally finite
Cayley graph on which SAWs have positive speed - this implies that the mean
square displacement exponent $\nu=1$ on such graphs.
  These results are obtained by proving more general theorems for SAWs on
quasi-transitive graphs with more than one end, which make use of a variation
of Kesten's pattern theorem in a surprising way, as well as the Stalling's
splitting theorem. Applications include proving that SAWs have positive speed
on the square grid in an infinite cylinder, and on the infinite free product
graph of two connected, quasi-transitive graphs.


title: Transfer Matrix of Scatterers Connected in Parallel

abstract:
  Transport phenomena in parallel coupled scatterers are studied by transfer
matrix formulism. We derive a simple recurrence relation for transfer matrix of
one-dimensional two-terminal systems consisting of $N$ arbitrary scattering
unit cells connected in parallel. For identical scattering sub-units we find
that the effects of parallel connection on transport properties of the coupled
system can be described by a similarity transformation on the single scatterer,
with the similar matrix determined by the scattering matrix of the junction.
While for distinct single scatterers, the similar matrices depend on both
scattering properties of individual elements and structure of connection
topologies.


title:
Secure and reliable connectivity in heterogeneous wireless sensor
  networks

abstract:
  We consider wireless sensor networks secured by the heterogeneous random key
predistribution scheme under an on/off channel model. The heterogeneous random
key predistribution scheme considers the case when the network includes sensor
nodes with varying levels of resources, features, or connectivity requirements;
e.g., regular nodes vs. cluster heads, but does not incorporate the fact that
wireless channel are unreliable. To capture the unreliability of the wireless
medium, we use an on/off channel model; wherein, each wireless channel is
either on (with probability $\alpha$) or off (with probability $1-\alpha$)
independently. We present conditions (in the form of zero-one laws) on how to
scale the parameters of the network model so that with high probability the
network is $k$-connected, i.e., the network remains connected even if any $k-1$
nodes fail or leave the network. We also present numerical results to support
these conditions in the finite-node regime.


title: Multiscale Computing in the Exascale Era

abstract:
  We expect that multiscale simulations will be one of the main high
performance computing workloads in the exascale era. We propose multiscale
computing patterns as a generic vehicle to realise load balanced, fault
tolerant and energy aware high performance multiscale computing. Multiscale
computing patterns should lead to a separation of concerns, whereby application
developers can compose multiscale models and execute multiscale simulations,
while pattern software realises optimized, fault tolerant and energy aware
multiscale computing. We introduce three multiscale computing patterns, present
an example of the extreme scaling pattern, and discuss our vision of how this
may shape multiscale computing in the exascale era.


title:
Spontaneous Proximity Clouds: Making Mobile Devices to Collaborate for
  Resource and Data Sharing

abstract:
  The base motivation of Mobile Cloud Computing was empowering mobile devices
by application offloading onto powerful cloud resources. However, this goal
can't entirely be reached because of the high offloading cost imposed by the
long physical distance between the mobile device and the cloud. To address this
issue, we propose an application offloading onto a nearby mobile cloud composed
of the mobile devices in the vicinity-a Spontaneous Proximity Cloud. We
introduce our proposed dynamic, ant-inspired, bi-objective offloading
middleware-ACOMMA, and explain its extension to perform a close mobile
application offloading. With the learning-based offloading decision-making
process of ACOMMA, combined to the collaborative resource sharing, the mobile
devices can cooperate for decision cache sharing. We evaluate the performance
of ACOMMA in collaborative mode with real benchmarks Face Recognition and
Monte-Carlo algorithms-and achieve 50% execution time gain.


title:
Symmetry-Breaking Transition and Spectral Singularity in Coupled
  $\mathcal{PT}$-Symmetric Quantum Potentials

abstract:
  We study the scattering properties of $N$ identical one-dimensional localized
$\mathcal{PT}$-symmetric potentials, connected in series as well as in
parallel. We derive a general transfer matrix formalism for parallel coupled
quantum scatterers, and apply that theory to demonstrate that the spectral
singularities and $\mathcal{PT}$-symmetric transitions of single scattering
cells may be observed in coupled systems, at the same or distinct values of the
critical parameters, depending on the connection modes under which the
scattering objects are coupled. We analyse the influences of the connection
configuration on the related transport properties such as spectral
singularities and anisotropic transmission resonances.


title: Quantum subdiffusion with two- and three-body interactions

abstract:
  We study the dynamics of a few-quantum-particle cloud in the presence of two-
and three-body interactions in weakly disordered one-dimensional lattices. The
interaction is dramatically enhancing the Anderson localization length $\xi_1$
of noninteracting particles. We launch compact wave packets and show that
few-body interactions lead to transient subdiffusion of wave packets, $m_2 \sim
t^{\alpha}$, $\alpha<1$, on length scales beyond $\xi_1$. The subdiffusion
exponent is independent of the number of particles. Two-body interactions yield
$\alpha\approx0.5$ for two and three particles, while three-body interactions
decrease it to $\alpha\approx0.2$. The tails of expanding wave packets exhibit
exponential localization with a slowly decreasing exponent. We relate our
results to subdiffusion in nonlinear random lattices, and to results on
restricted diffusion in high-dimensional spaces like e.g. on comb lattices.


title: A method to calculate inductance in systems of parallel wires

abstract:
  This paper gives a method that maps the static magnetic field due to a system
of parallel current-carrying wires to a complex function. Using this function
simplifies the calculation of the magnetic field energy density and inductance
per length in the wires, and we reproduce well-known results for this case.


title:
Minimal free resolutions for homogeneous ideals with Betti numbers
  $1,n,n,1$

abstract:
  We investigate the standard generalized Gorenstein algebras of homological
dimension three, giving a structure theorem for their resolutions. Moreover in
many cases we are able to give a complete description of their graded Betti
numbers.


title:
Structure, minimal generating systems and properties of Sylow
  2-subgroups of alternating group

abstract:
  The background of this paper is the following: search of the minimal systems
of generators for this class of group which still was not founded also problem
of representation for this class of group, exploration of systems of generators
for Sylow 2-subgroups $Syl_2{A_{2^k}}$ and $Syl_2{A_{n}}$ of alternating group,
finding structure of these subgroups.
  The authors of article "Structure of 2-sylow subgroup of symmetric and
alternating group" U.~Dmitruk, V.~Suschansky didn't proof minimality of finding
by them system of generators for such Sylow 2-subgroups of $A_n$ and structure
of it were founded only descriptively.
  The aim of this paper is to research the structure of Sylow 2-subgroups and
to construct a minimal generating system for such subgroups. In other words,
the problem is not simply in the proof of existence of a generating set with
elements for Sylow 2-subgroup of alternating group of degree $2^k$ and its
constructive proof and proof its minimality. For the construction of minimal
generating set we used the representation of elements of group by automorphisms
of portraits for binary tree. Also, the goal of this paper is to investigate
the structure of 2-sylow subgroup of alternating group more exactly and deep
than in articlle of U.~Dmitruk and V.~Suschansky.
  The main result is the proof of minimality of this generating set of the
above described subgroups and also the description of their structure. Key
words: minimal system of generators; wreath product; Sylow subgroups; group;
semidirect product.


title:
Optimizing future experiments of cosmic far-infrared background: a
  principal component approach

abstract:
  The anisotropies of cosmic far-infrared background (CFIRB) probe the star
formation rate (SFR) of dusty star-forming galaxies as a function of dark
matter halo mass and redshift. We explore how future CFIRB experiments can
optimally improve the SFR constraints beyond the current measurements of
Planck. We introduce a model-independent, piecewise parametrization for SFR as
a function of halo mass and redshift, and we calculate the Fisher matrix and
principal components of these parameters to estimate the SFR constraints of
future experiments. We investigate how the SFR constraints depend on angular
resolution, number and range of frequency bands, survey coverage, and
instrumental sensitivity. We find that the angular resolution and the
instrumental sensitivity play the key roles. Improving the angular resolution
from 20 to 4 arcmin can improve the SFR constraints by 1.5 - 2.5 orders of
magnitude. With the angular resolution of Planck, improving the sensitivity by
10 or 100 times can improve the SFR constraints by one or two orders of
magnitude, and doubling the number of frequency bands can also improve the SFR
constraints by an order of magnitude. We find that survey designs like the
Cosmic Origins Explorer (CORE) are very close to the optimal design for
improving the SFR constraints at all redshifts, while survey designs like
LiteBIRD and CMB-S4 can significantly improve the SFR constraints at z>3.


title:
The interpretation of the multi-wavelength afterglow emission of short
  GRB 140903A

abstract:
  GRB 140903A, a short duration $\gamma-$ray burst (SGRB) detected by {\it
Swift}, is characterized by its long-lasting radio emission among SGRBs. In
addition to the $\sim 10^{6}$ s radio afterglow emission, the afterglow of GRB
140903A displays a plateau from $10^3$ s to $7 \times 10^3 $ s in the X-rays.
In this work, we attribute the X-ray plateau to the energy injection into the
decelerating blast wave and then model the later radio/optical/X-ray afterglow
emission within the standard fireball afterglow model. The afterglow emission
has been well reproduced with reasonable physical parameters, including a jet
half-opening angle $\sim 0.05$. We also compare the physical properties of
SGRBs with and without radio afterglow detections and find that nearby SGRBs
are brighter and easier to be detected in radio. Such a phenomena has been
interpreted within the afterglow model.


title: I-primary submodules

abstract:
  In this paper, we give a generalization for weakly primary submodules called
$I$-primary submodule and we study some properties of it. We give some
characterizations of $I$-primary submodules. Also we establish the situation of
$I$-primary submodules in module localizations and decomposition modules.


title:
Non-equilibrium study of the Chiral Magnetic Effect from real-time
  simulations with dynamical fermions

abstract:
  We present a real-time lattice approach to study the non-equilibrium dynamics
of vector and axial charges in $SU(N) \times U(1)$ gauge theories. Based on a
classical description of the non-Abelian and Abelian gauge fields, we include
dynamical fermions and develop operator definitions for (improved) Wilson and
overlap fermions that allow us to study real-time manifestations of the axial
anomaly from first principles. We present a first application of this approach
to anomalous transport phenomena such as the Chiral Magnetic Effect (CME) and
Chiral Separation Effect (CSE) by studying the dynamics of fermions during and
after a $SU(N)$ sphaleron transition in the presence of a $U(1)$ magnetic
field. We investigate the fermion mass and magnetic field dependence of the
suggested signatures of the CME and CSE and point out some important aspects
which need to be accounted for in the macroscopic description of anomalous
transport phenomena.


title: Decay of correlations in 2D quantum systems with continuous symmetry

abstract:
  We study a large class of models of two-dimensional quantum lattice systems
with continuous symmetries, and we prove a general McBryan-Spencer-Koma-Tasaki
theorem concerning algebraic decay of correlations. We present applications of
our main result to the Heisenberg-, Hubbard-, and t-J models, and to certain
models of random loops.


title: Harmony of Spinning Conformal Blocks

abstract:
  Conformal blocks for correlation functions of tensor operators play an
increasingly important role for the conformal bootstrap programme. We develop a
universal approach to such spinning blocks through the harmonic analysis of
certain bundles over a coset of the conformal group. The resulting Casimir
equations are given by a matrix version of the Calogero-Sutherland Hamiltonian
that describes the scattering of interacting spinning particles in a
1-dimensional external potential. The approach is illustrated in several
examples including fermionic seed blocks in 3D CFT where they take a very
simple form.


title: Qubits and STU Black Holes with Eight Electric and Magnetic Charges

abstract:
  In this work, we consider a STU black-hole model containing eight magnetic
and eight electric charges ((8+8)-signature). We show that such model admits an
extremal black holes solution in which (8+8)-signature can be associated with
the entropy via the Cayley's hyperdeterminant.


title: Generalizations of the short pulse equation

abstract:
  We classify integrable scalar polynomial partial differential equations of
second order generalizing the short pulse equation.


title:
Improving the Performance of Neural Machine Translation Involving
  Morphologically Rich Languages

abstract:
  The advent of the attention mechanism in neural machine translation models
has improved the performance of machine translation systems by enabling
selective lookup into the source sentence. In this paper, the efficiencies of
translation using bidirectional encoder attention decoder models were studied
with respect to translation involving morphologically rich languages. The
English - Tamil language pair was selected for this analysis. First, the use of
Word2Vec embedding for both the English and Tamil words improved the
translation results by 0.73 BLEU points over the baseline RNNSearch model with
4.84 BLEU score. The use of morphological segmentation before word
vectorization to split the morphologically rich Tamil words into their
respective morphemes before the translation, caused a reduction in the target
vocabulary size by a factor of 8. Also, this model (RNNMorph) improved the
performance of neural machine translation by 7.05 BLEU points over the
RNNSearch model used over the same corpus. Since the BLEU evaluation of the
RNNMorph model might be unreliable due to an increase in the number of matching
tokens per sentence, the performances of the translations were also compared by
means of human evaluation metrics of adequacy, fluency and relative ranking.
Further, the use of morphological segmentation also improved the efficacy of
the attention mechanism.


title: High Dimensional Consistent Digital Segments

abstract:
  We consider the problem of digitalizing Euclidean line segments from
$\mathbb{R}^d$ to $\mathbb{Z}^d$. Christ {\em et al.} (DCG, 2012) showed how to
construct a set of {\em consistent digital segment} (CDS) for $d=2$: a
collection of segments connecting any two points in $\mathbb{Z}^2$ that
satisfies the natural extension of the Euclidean axioms to $\mathbb{Z}^d$. In
this paper we study the construction of CDSs in higher dimensions.
  We show that any total order can be used to create a set of {\em consistent
digital rays} CDR in $\mathbb{Z}^d$ (a set of rays emanating from a fixed point
$p$ that satisfies the extension of the Euclidean axioms). We fully
characterize for which total orders the construction holds and study their
Hausdorff distance, which in particular positively answers the question posed
by Christ {\em et al.}.


title:
Exploring the effects of a double reconstruction on the growth rate of
  cosmic structure, using current observational data

abstract:
  Based on General Relativity (GR) we consider two different cosmological
scenarios in where reconstruct the energy exchange (Q) between cold dark matter
(DM) fluid and dark energy (DE) fluid, which is modelled with a DE varying
equation of state (EoS) parameter {\omega}. We here investigate the main
cosmological effects on the growth rate of matter density perturbations
(f{\sigma}8), on the effective Hubble friction term (Heff ), on the effective
Newton constant (Geff ) and on the growth index of the linear matter
fluctuations ({\gamma}). Our study demonstrates that in the coupled models the
evolution of these quantities are modified with respect to the predictions in
the uncoupled models, and therefore could be used to distinguish among coupled
DE scenarios. Finally, we also perform a combined statistical analysis using
current observational data (geometric and dynamical probes) to put more
stringent constraints on the parameters space of the cosmic scenarios studied.


title:
Comparative Evaluation of Big-Data Systems on Scientific Image Analytics
  Workloads

abstract:
  Scientific discoveries are increasingly driven by analyzing large volumes of
image data. Many new libraries and specialized database management systems
(DBMSs) have emerged to support such tasks. It is unclear, however, how well
these systems support real-world image analysis use cases, and how performant
are the image analytics tasks implemented on top of such systems. In this
paper, we present the first comprehensive evaluation of large-scale image
analysis systems using two real-world scientific image data processing use
cases. We evaluate five representative systems (SciDB, Myria, Spark, Dask, and
TensorFlow) and find that each of them has shortcomings that complicate
implementation or hurt performance. Such shortcomings lead to new research
opportunities in making large-scale image analysis both efficient and easy to
use.


title:
A Universal Multi-Hierarchy Figure-of-Merit for On-Chip Computing and
  Communications

abstract:
  Continuing demands for increased compute efficiency and communication
bandwidth have led to the development of novel interconnect technologies with
the potential to outperform conventional electrical interconnects. With a
plurality of interconnect technologies to include electronics, photonics,
plasmonics, and hybrids thereof, the simple approach of counting on-chip
devices to capture performance is insufficient. While some efforts have been
made to capture the performance evolution more accurately, they eventually
deviate from the observed development pace. Thus, a holistic figure of merit
(FOM) is needed to adequately compare these recent technology paradigms. Here
we introduce the Capability-to-Latency-Energy-Amount-Resistance (CLEAR) FOM
derived from device and link performance criteria of both active optoelectronic
devices and passive components alike. As such CLEAR incorporates communication
delay, energy efficiency, on-chip scaling and economic cost. We show that CLEAR
accurately describes compute development including most recent machines. Since
this FOM is derived bottom-up, we demonstrate remarkable adaptability to
applications ranging from device-level to network and system-level. Applying
CLEAR to benchmark device, link, and network performance against fundamental
physical compute and communication limits shows that photonics is competitive
even for fractions of the die-size, thus making a case for on-chip optical
interconnects.


title:
Interactive Elicitation of Knowledge on Feature Relevance Improves
  Predictions in Small Data Sets

abstract:
  Providing accurate predictions is challenging for machine learning algorithms
when the number of features is larger than the number of samples in the data.
Prior knowledge can improve machine learning models by indicating relevant
variables and parameter values. Yet, this prior knowledge is often tacit and
only available from domain experts. We present a novel approach that uses
interactive visualization to elicit the tacit prior knowledge and uses it to
improve the accuracy of prediction models. The main component of our approach
is a user model that models the domain expert's knowledge of the relevance of
different features for a prediction task. In particular, based on the expert's
earlier input, the user model guides the selection of the features on which to
elicit user's knowledge next. The results of a controlled user study show that
the user model significantly improves prior knowledge elicitation and
prediction accuracy, when predicting the relative citation counts of scientific
documents in a specific domain.


title: NMR Contributions to the study of Quantum Correlations

abstract:
  In this chapter we review the contributions of Nuclear Magnetic Resonance to
the study of quantum correlations, including its capabilities to prepare
initial states, generate unitary transformations, and characterize the final
state. These are the three main demands to implement quantum information
processing in a physical system, which NMR offers, nearly to perfection, though
for a small number of qubits. Our main discussion will concern liquid samples
at room temperature.


title: Global weak solutions for SQG in bounded domains

abstract:
  We prove existence of global weak $L^2$ solutions of the inviscid SQG
equation in bounded domains.


title:
Bridging Medical Data Inference to Achilles Tendon Rupture
  Rehabilitation

abstract:
  Imputing incomplete medical tests and predicting patient outcomes are crucial
for guiding the decision making for therapy, such as after an Achilles Tendon
Rupture (ATR). We formulate the problem of data imputation and prediction for
ATR relevant medical measurements into a recommender system framework. By
applying MatchBox, which is a collaborative filtering approach, on a real
dataset collected from 374 ATR patients, we aim at offering personalized
medical data imputation and prediction. In this work, we show the feasibility
of this approach and discuss potential research directions by conducting
initial qualitative evaluations.


title: Rethinking the Experiment

abstract:
  The crisis in the reproducibility of experiments invites a re-evaluation of
methods of inquiry and validation procedures. The text challenges current
assumptions of knowledge acquisition and introduces G-complexity for defining
decidable vs. non-decidable knowledge domains. A "second Cartesian revolution,"
informed by and in awareness of anticipatory processes, should result in
scientific methods that transcend determinism and reductionism. Physics and
physics-based disciplines convincingly ascertained themselves by adequately
describing the non-living. A complementary perspective should account for the
specific causality characteristic of life by integrating past, present, and
future. Knowledge about anticipatory processes facilitates attainment of this
goal. Society cannot afford the dead-end street of reductionism. Science,
itself an expression of anticipatory activity, makes possible in our days
alternative understandings of reality and its dynamics.


title: Graphene-based Solitons for Spatial Division Multiplexed Switching

abstract:
  Spatial division multiplexing utilizes the directionality of lights
propagating k-vector to separate it into distinct spatial directions. Here we
show that the anisotropy of orthogonal spatial Solitons propagating in a single
Graphene monolayer results in phase-based multiplexing. We use the self-
confinement properties of spatial Solitons to increase the usable density of
states (DOS) of this switching-system. Furthermore, we show that crossing two
orthogonal Solitons exhibit a low (0.035 dB) mutual disturbance from another
enabling independent k-vector switching. The efficient utilization of the DOS
and multiplexing in real-space enables data processing parallelism with
applications in optical networking and computing.


title:
Research on the Multiple Feature Fusion Image Retrieval Algorithm based
  on Texture Feature and Rough Set Theory

abstract:
  Recently, we have witnessed the explosive growth of images with complex
information and content. In order to effectively and precisely retrieve desired
images from a large-scale image database with low time-consuming, we propose
the multiple feature fusion image retrieval algorithm based on the texture
feature and rough set theory in this paper. In contrast to the conventional
approaches that only use the single feature or standard, we fuse the different
features with operation of normalization. The rough set theory will assist us
to enhance the robustness of retrieval system when facing with incomplete data
warehouse. To enhance the texture extraction paradigm, we use the wavelet Gabor
function that holds better robustness. In addition, from the perspectives of
the internal and external normalization, we re-organize extracted feature with
the better combination. The numerical experiment has verified general
feasibility of our methodology. We enhance the overall accuracy compared with
the other state-of-the-art algorithms.


title:
Active Material, Optical Mode and Cavity Impact on electro-optic
  Modulation Performance

abstract:
  In this paper, three different materials Si, ITO and graphene; and three
different types of mode structures bulk, slot and hybrid; based on their
electrooptical and electro absorptive aspects in performance are analyzed. The
study focuses on three major characteristics of electrooptic tuning, i.e.
material, modal and cavity dependency. The materials are characterized with
established models and the allowed ranges for their key parameter spectra are
analyzed with desired tuning in mind; categorizing into n and k dominant
regions for plausible electrooptic and electro absorptive applications,
respectively. A semi analytic approach, with the aid of FEM simulations for the
eigenmode calculations, was used for this work. Electrooptic tuning i.e.
resonance shift properties inside Fabry Perot cavities are investigated with
modal and scaling concerns in mind. Tuning changes the effective complex
refractive index of the mode dictated by the Kramers Kronig relations which
subsequently suggest a tradeoff between the resonance shift and increasing
losses. The electrical tuning properties of the different modes in the cavity
are analyzed, and subsequently a figure of merit, delta-lambda/delta-alpha was
chosen with respect to carrier concentration and cavity scaling to find
prospective suitable regions for desired tuning effects.


title:
An initial investigation of the performance of GPU-based swept
  time-space decomposition

abstract:
  Simulations of physical phenomena are essential to the expedient design of
precision components in aerospace and other high-tech industries. These
phenomena are often described by mathematical models involving partial
differential equations (PDEs) without exact solutions. Modern design problems
require simulations with a level of resolution that is difficult to achieve in
a reasonable amount of time even in effectively parallelized solvers. Though
the scale of the problem relative to available computing power is the greatest
impediment to accelerating these applications, significant performance gains
can be achieved through careful attention to the details of memory accesses.
Parallelized PDE solvers are subject to a trade-off in memory management: store
the solution for each timestep in abundant, global memory with high access
costs or in a limited, private memory with low access costs that must be passed
between nodes. The GPU implementation of swept time-space decomposition
presented here mitigates this dilemma by using private (shared) memory,
avoiding internode communication, and overwriting unnecessary values. It shows
significant improvement in the execution time of the PDE solvers in one
dimension achieving speedups of 6-2x for large and small problem sizes
respectively compared to naive GPU versions and 7-300x compared to parallel CPU
versions.


title: Thermodynamics of low-dimensional trapped Fermi gases

abstract:
  The effects of low dimensionality on the thermodynamics of a Fermi gas
trapped by isotropic power law potentials are analyzed. Particular attention is
given to different characteristic temperatures that emerge, at low
dimensionality, in the thermodynamic functions of state and in the
thermodynamic susceptibilities (isothermal compressibility and specific heat).
An energy-entropy argument that physically favors the relevance of one of these
characteristic temperatures, namely, the non vanishing temperature at which the
chemical potential reaches the Fermi energy value, is presented. Such an
argument allows to interpret the nonmonotonic dependence of the chemical
potential on temperature, as an indicator of the appearance of a thermodynamic
regime, where the equilibrium states of a trapped Fermi gas are characterized
by larger fluctuations in energy and particle density as is revealed in the
corresponding thermodynamics susceptibilities.


title: Representation Embeddings of Cartesian Theories

abstract:
  A representation embedding between cartesian theories can be defined to be a
functor between respective categories of models that preserves
finitely-generated projective models and that preserves and reflects certain
epimorphisms. This recalls standard definitions in the representation theory of
associative algebras. The main result of this paper is that a representation
embedding in the general sense preserves undecidability of theories. This
result is applied to obtain an affirmative resolution of a reformulation in
cartesian logic of a conjecture of M. Prest that every wild algebra over an
algebraically closed field has an undecidable theory of modules.


title: Discrete Schroedinger Transform For Texture Recognition

abstract:
  This work presents a new procedure to extract features of grey-level texture
images based on the discrete Schroedinger transform. This is a non-linear
transform where the image is mapped as the initial probability distribution of
a wave function and such distribution evolves in time following the
Schroedinger equation from Quantum Mechanics. The features are provided by
statistical moments of the distribution measured at different times. The
proposed method is applied to the classification of three databases of textures
used for benchmark and compared to other well-known texture descriptors in the
literature, such as textons, local binary patterns, multifractals, among
others. All of them are outperformed by the proposed method in terms of
percentage of images correctly classified. The proposal is also applied to the
identification of plant species using scanned images of leaves and again it
outperforms other texture methods. A test with images affected by Gaussian and
"salt \& pepper" noise is also carried out, also with the best performance
achieved by the Schroedinger descriptors.


title:
Quarkonium measurements via the di-muon decay channel in $\rm p$+$\rm p$
  and $\rm Au$+$\rm Au$ collisions with the STAR experiment

abstract:
  We present the first $J/\psi$ and $\Upsilon$ measurements in the di-muon
decay channel at mid-rapidity at RHIC using the newly installed Muon Telescope
Detector. In p$+$p collisions at $\sqrt{s}=500$~GeV, inclusive $J/\psi$ cross
section can be described by CGC+NRQCD and NLO NRQCD model calculations for
$0<p_T<20$~GeV/$c$. In Au$+$Au collisions at $\sqrt{s_{NN}}=200$~GeV, we
observe (i) clear $J/\psi$ suppression indicating dissociation; (ii) $J/\psi$
$R_{AA}$ can be qualitatively described by transport models including
dissociation and regeneration with a tension at high $p_T$; and (iii) hint of
less melting of $\Upsilon(2S+3S)$ relative to $\Upsilon(1S)$ at RHIC compared
to that at LHC.


title: Quasidense monotone multifunctions

abstract:
  In this paper, we discuss quasidense multifunctions from a Banach space into
its dual, and use the two sum theorems proved in a previous paper to give
various characterizations of quasidensity. We investigate the Fitzpatrick
extension of such a multifunction. We prove that, for closed monotone
multifunctions, quasidensity implies type (FPV) and strong maximality, and that
quasidensity is equivalent to type (FP). This version differs from Version 3 in
that a few minor errors have been corrected.


title:
Direct and Inverse Cascades in the Acceleration Region of the Fast Solar
  Wind

abstract:
  Alfv\'{e}n waves are believed to play an important role in the heating and
acceleration of the fast solar wind emanating from coronal holes. Nonlinear
interactions between the dominant ${\bf z}_{+}$ waves and minority ${\bf
z}_{-}$ waves have the potential to transfer wave energy either to smaller
perpendicular scales ("direct cascade") or to larger scales ("inverse
cascade"). In this paper we use reduced magnetohydrodynamic (RMHD) simulations
to investigate how the cascade rates $\epsilon_{\pm}$ depend on perpendicular
wavenumber and radial distance from Sun center. For models with a smooth
background atmosphere we find that an inverse cascade ($\epsilon_{+} < 0$)
occurs for the dominant waves at radii between 1.4 and 2.5 $R_\odot$ and
dimensionless wavenumbers in the inertial range ($15 < a_\perp < 44$), and a
direct cascade ($\epsilon_{+} > 0$) occurs elsewhere. For a model with density
fluctuations there are multiple regions with inverse cascade. In both cases the
cascade rate $\epsilon_{+}$ varies significantly with perpendicular wavenumber,
indicating that the cacsade is a highly non-local process. As a result of the
inverse cascades, the enery dissipation rates are much lower than expected from
a phenomenological model, and are insufficient to maintain the temperature of
the background atmosphere. We conclude that RMHD models are unable to reproduce
the observed properties of the fast solar wind.


title: Superconductivity in higher titanium oxides

abstract:
  Recent renewal of the highest transition temperature in a conventional
superconductor of the sulfer hydride attracts much attention to exploring
simple compounds with the lighter elements, situated in unconventional
conditions. We report the discovery of superconductivity in simple oxides of
Ti4O7 and g-Ti3O5 in a thin-film form having deliberately tuned epitaxial
structures and off-stoichiometry. These higher titanium oxides join in a class
of simple-oxide superconductors, and g-Ti3O5 now holds the highest
superconducting transition temperature of 7.1 kelvin among them. The mechanism
behind the superconductivity is discussed on the basis of electrical
measurements and theoretical predictions. We conclude that superconductivity
arises from unstabilized bipolaronic insulating states.


title:
What do Shannon-type Inequalities, Submodular Width, and Disjunctive
  Datalog have to do with one another?

abstract:
  Recent works on bounding the output size of a conjunctive query with
functional dependencies and degree constraints have shown a deep connection
between fundamental questions in information theory and database theory. We
prove analogous output bounds for disjunctive datalog rules, and answer several
open questions regarding the tightness and looseness of these bounds along the
way. Our bounds are intimately related to Shannon-type information
inequalities. We devise the notion of a "proof sequence" of a specific class of
Shannon-type information inequalities called "Shannon flow inequalities". We
then show how such a proof sequence can be interpreted as symbolic instructions
guiding an algorithm called "PANDA", which answers disjunctive datalog rules
within the time that the size bound predicted. We show that PANDA can be used
as a black-box to devise algorithms matching precisely the fractional hypertree
width and the submodular width runtimes for aggregate and conjunctive queries
with functional dependencies and degree constraints.
  Our results improve upon known results in three ways. First, our bounds and
algorithms are for the much more general class of disjunctive datalog rules, of
which conjunctive queries are a special case. Second, the runtime of PANDA
matches precisely the submodular width bound, while the previous algorithm by
Marx has a runtime that is polynomial in this bound. Third, our bounds and
algorithms work for queries with input cardinality bounds, functional
dependencies, and degree constraints.
  Overall, our results show a deep connection between three seemingly unrelated
lines of research; and, our results on proof sequences for Shannon flow
inequalities might be of independent interest.


title:
Hamiltonian Formulation of the Conservative Self-Force Dynamics in the
  Kerr Geometry

abstract:
  We formulate a Hamiltonian description of the orbital motion of a point
particle in Kerr spacetime for generic (eccentric, inclined) orbits, which
accounts for the effects of the conservative part of the gravitational
self-force. This formulation relies on a description of the particle's motion
as geodesic in a certain smooth effective spacetime, in terms of (generalized)
action-angle variables. Clarifying the role played by the gauge freedom in the
Hamiltonian dynamics, we extract the gauge-invariant information contained in
the conservative self-force. We also propose a possible gauge choice for which
the orbital dynamics can be described by an effective Hamiltonian, written
solely in terms of the action variables. As an application of our Hamiltonian
formulation in this gauge, we derive the conservative self-force correction to
the orbital frequencies of Kerr innermost stable spherical (inclined or
circular) orbits. This gauge choice also allows us to establish a "first law of
mechanics" for black-hole-particle binary systems, at leading order beyond the
test-mass approximation.


title:
Coexistence of magnetic order and valence fluctuations in the Kondo
  lattice system Ce$_2$Rh$_3$Sn$_5$

abstract:
  We report on the electronic band structure, structural, magnetic and thermal
properties of Ce$_2$Rh$_3$Sn$_5$. Ce $L_{\mathrm{III}}$-edge XAS spectra give
direct evidence for an intermediate valence behaviour. Thermodynamic
measurements reveal magnetic transitions at $T_{\mathrm{N1}}\approx$ 2.9 K and
$T_{\mathrm{N2}}\approx$ 2.4 K. Electrical resistivity shows behaviour typical
for Kondo lattices. The coexistence of magnetic order and valence fluctuations
in a Kondo lattice system we attribute to a peculiar crystal structure in which
Ce ions occupy two distinct lattice sites. Analysis of the structural features
of Ce$_2$Rh$_3$Sn$_5$, together with results of electronic band structure
calculations and thermodynamic data indicate that Ce2 ions are in an
intermediate valence state with the ground state electronic configuration close
to 4$f^0$, whereas Ce1 ions are trivalent (4$f^1$) and contribute to the low
temperature magnetic ordering. Thus, our joined experimental and theoretical
investigations classify Ce$_2$Rh$_3$Sn$_5$ as a multivalent charge-ordered
system.


title: Gradient descent in a generalised Bregman distance framework

abstract:
  We discuss a special form of gradient descent that in the literature has
become known as the so-called linearised Bregman iteration. The idea is to
replace the classical (squared) two norm metric in the gradient descent setting
with a generalised Bregman distance, based on a more general proper, convex and
lower semi-continuous functional. Gradient descent as well as the entropic
mirror descent by Nemirovsky and Yudin are special cases, as is a specific form
of non-linear Landweber iteration introduced by Bachmayr and Burger. We are
going to analyse the linearised Bregman iteration in a setting where the
functional we want to minimise is neither necessarily Lipschitz-continuous (in
the classical sense) nor necessarily convex, and establish a global convergence
result under the additional assumption that the functional we wish to minimise
satisfies the so-called Kurdyka-{\L}ojasiewicz property.


title:
Asteroseismic Constraints on the Models of Hot B Subdwarfs: Convective
  Helium-Burning Cores

abstract:
  Asteroseismology of non-radial pulsations in Hot B Subdwarfs (sdB stars)
offers a unique view into the interior of core-helium-burning stars.
Ground-based and space-borne high precision light curves allow for the analysis
of pressure and gravity mode pulsations to probe the structure of sdB stars
deep into the convective core. As such asteroseismological analysis provides an
excellent opportunity to test our understanding of stellar evolution. In light
of the newest constraints from asteroseismology of sdB and red clump stars,
standard approaches of convective mixing in 1D stellar evolution models are
called into question. The problem lies in the current treatment of overshooting
and the entrainment at the convective boundary. Unfortunately no consistent
algorithm of convective mixing exists to solve the problem, introducing
uncertainties to the estimates of stellar ages. Three dimensional simulations
of stellar convection show the natural development of an overshooting region
and a boundary layer. In search for a consistent prescription of convection in
one dimensional stellar evolution models, guidance from three dimensional
simulations and asteroseismological results is indispensable.


title:
Action of the mapping class group on character varieties and Higgs
  bundles

abstract:
  We consider the action of a finite subgroup of the mapping class group
$Mod(S)$ of an oriented compact surface $S$ of genus $g \geq 2$ on the moduli
space $\mathcal{R}(S,G)$ of representations of $\pi_1(S)$ in a connected
semisimple real Lie group $G$. Kerckhoff's solution of the Nielsen realization
problem ensures the existence of an element $J$ in the Teichm\"uller space of
$S$ for which $\Gamma$ can be realised as a subgroup of the group of
automorphisms of $X=(S,J)$ which are holomorphic or antiholomorphic. We
identify the fixed points of the action of $\Gamma$ on $\mathcal{R}(S,G)$ in
terms of $G$-Higgs bundles on $X$ equipped with a certain twisted
$\Gamma$-equivariant structure, where the twisting involves abelian and
non-abelian group cohomology simultaneously. When the kernel of the isotropy
representation of the maximal compact subgroup of $G$ is trivial, the fixed
points can be described in terms of familiar objects on $Y=X/\Gamma^+$, where
$\Gamma^+ \subset \Gamma$ is the maximal subgroup of $\Gamma$ consisting of
holomorphic automorphisms of $X$. If $\Gamma=\Gamma^+$ one obtains actual
$\Gamma$-equivariant $G$-Higgs bundles on $X$, which in turn correspond with
parabolic Higgs bundles on $Y=X/\Gamma$ (this generalizes work of Nasatyr \&
Steer for $G=SL(2,\mathbb{R})$ and Boden, Andersen & Grove and Furuta & Steer
for $G=SU(n)$). If on the other hand $\Gamma$ has antiholomorphic
automorphisms, the objects on $Y=X/\Gamma^+$ correspond with pseudoreal
parabolic Higgs bundles. This is a generalization in the parabolic setup of the
pseudoreal Higgs bundles studied by the first author in collaboration with
Biswas & Hurtubise.


title: Geodesics using Waves: Computing Distances using Wave Propagation

abstract:
  In this paper, we present a new method for computing approximate geodesic
distances. We introduce the wave method for approximating geodesic distances
from a point on a manifold mesh. Our method involves the solution of two linear
systems of equations. One system of equations is solved repeatedly to propagate
the wave on the entire mesh, and one system is solved once after wave
propagation is complete in order to compute the approximate geodesic distances
up to an additive constant. However, these systems need to be pre-factored only
once, and can be solved efficiently at each iteration. All of our tests
required approximately between 300 and 400 iterations, which were completed in
a few seconds. Therefore, this method can approximate geodesic distances
quickly, and the approximation is highly accurate.


title:
ALMA Compact Array observations of the Fried Egg nebula: Evidence for
  large-scale asymmetric mass-loss from the yellow hypergiant IRAS 17163-3907

abstract:
  Yellow hypergiants are rare and represent a fast evolutionary stage of
massive evolved stars. That evolutionary phase is characterised by a very
intense mass loss, the understanding of which is still very limited. Here we
report ALMA Compact Array observations of a 50$"$-mosaic toward the Fried Egg
nebula, around one of the few Galactic yellow hypergiants IRAS 17163-3907. The
emission from the $^{12}$CO J=2-1 line, H30$\alpha$ recombination line, and
continuum is imaged at a resolution of $\sim$8$"$, revealing the morphology of
the molecular environment around the star. The continuum emission is unresolved
and peaks at the position of the star. The radio recombination line H30$\alpha$
shows unresolved emission at the star, with an approximately gaussian spectrum
centered on a velocity of 21$\pm$3~km/s with a width of 57$\pm$6~km/s. In
contrast, the CO 2-1 emission is complex and decomposes into several components
beyond the contamination from interstellar gas in the line of sight. The CO
spectrum toward the star is a broad plateau, centered at the systemic velocity
of +18 km/s and with an expansion velocity of 100$\pm$10 km/s. Assuming
isotropic and constant mass-loss, we estimate a mass-loss rate of 8$\pm$1.5
$\times10^{-5}$~M$_\odot$ yr$^{-1}$. At a radius of 25$"$ from the star, we
detect CO emission associated with the dust ring previously imaged by {\it
Herschel}. The kinematics of this ring, however, is not consistent with an
expanding shell, but show a velocity gradient of $v_{sys} \pm$20 km/s. In
addition, we find a puzzling bright feature radially connecting the star to the
CO ring, at a velocity of +40 km/s relative to the star. This spur feature may
trace a unidirectional ejection event from the star. Our ACA observations
reveal the complex morphology around IRAS 17163 and illustrate the
breakthroughs that ALMA will bring to the field of massive stellar evolution.


title: Affleck-Dine Leptogenesis with Varying Peccei-Quinn Scale

abstract:
  The Affleck-Dine leptogenesis scenario along the LHu flat direction is
reconsidered. It is known that successful Affleck-Dine leptogenesis requires
that the lightest neutrino mass is extremely small. This situation can be
significantly relaxed if the neutrino mass in the early universe is different
from the present one. We consider a supersymmetric
Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) type model, which provides a solution
to the strong CP problem and generates a SUSY mu-term and right-handed neutrino
masses. If the PQ scale during lepton number generation is much larger than the
present value, leptogenesis is very efficient so that enough baryon number can
be generated without introducing a hierarchically small neutrino mass. The
final baryon asymmetry is related to the mu-term, and hence linked to the level
of electroweak fine-tuning. We also show the PQ breaking scalar dynamics that
keeps a large PQ breaking scale during inflation and lepton number generation.
The mu-term generating superpotential plays an important role for preserving
the lepton asymmetry during saxion oscillation. In this scenario, the axion
isocurvature perturbation is naturally suppressed.


title:
Estimation of social-influence-dependent peer pressures in a large
  network game

abstract:
  Research on peer effects in sociology has been focused for long on social
influence power to investigate the social foundations for social interactions.
This paper extends Xu(2011)'s large--network--based game model by allowing for
social-influence-dependent peer effects. In a large network, we use the
Katz--Bonacich centrality to measure individuals' social influences. To solve
the computational burden when the data come from the equilibrium of a large
network, we extend Aguirregabiria and Mira (2007)'s nested pseudo likelihood
estimation (NPLE) approach to our large network game model. Using the Add
Health dataset, we investigate peer effects on conducting dangerous behaviors
of high school students. Our results show that peer effects are statistically
significant and positive. Moreover, a student benefits more (statistically
significant at the 5% level) from her conformity, or equivalently, pays more
for her disobedience, in terms of peer pressures, if friends have higher
social-influence status.


title: Complex Matrix Factorization for Face Recognition

abstract:
  This work developed novel complex matrix factorization methods for face
recognition; the methods were complex matrix factorization (CMF), sparse
complex matrix factorization (SpaCMF), and graph complex matrix factorization
(GraCMF). After real-valued data are transformed into a complex field, the
complex-valued matrix will be decomposed into two matrices of bases and
coefficients, which are derived from solutions to an optimization problem in a
complex domain. The generated objective function is the real-valued function of
the reconstruction error, which produces a parametric description. Factorizing
the matrix of complex entries directly transformed the constrained optimization
problem into an unconstrained optimization problem. Additionally, a complex
vector space with N dimensions can be regarded as a 2N-dimensional real vector
space. Accordingly, all real analytic properties can be exploited in the
complex field. The ability to exploit these important characteristics motivated
the development herein of a simpler framework that can provide better
recognition results. The effectiveness of this framework will be clearly
elucidated in later sections in this paper.


title:
Thermal conductivity measurements of PTFE and Al$_2$O$_3$ ceramic at
  sub-Kelvin temperatures

abstract:
  The design of low temperature bolometric detectors for rare event searches
necessitates careful selection and characterization of structural materials
based on their thermal properties. We measure the thermal conductivities of
polytetrafluoroethylene (PTFE) and Al$_2$O$_3$ ceramic (alumina) in the
temperature ranges of 0.17-0.43 K and 0.1-1.3 K, respectively. For the former,
we observe a quadratic temperature dependence across the entire measured range.
For the latter, we see a cubic dependence on temperature above ~0.3 K, with a
linear contribution below that temperature. This paper presents our measurement
techniques, results, and theoretical discussions. Keywords: Thermal
Conductivity, PTFE, Al$_2$O$_3$ ceramic, Bolometer


title:
Damped spin-wave excitations in the itinerant antiferromagnet
  $\gamma$-Fe$_{0.7}$Mn$_{0.3}$

abstract:
  The collective spin-wave excitations in the antiferromagnetic state of
$\gamma$-Fe$_{0.7}$Mn$_{0.3}$ were investigated using the inelastic neutron
scattering technique. The spin excitations remain isotropic up to the high
excitation energy, ${\hbar\omega}= 78$ meV. The excitations gradually become
broad and damped above 40 meV. The damping parameter ${\gamma}$ reaches 110(16)
meV at ${\hbar\omega} = 78$ meV, which is much larger than that for other
metallic compounds, e.g., CaFe$_2$As$_2$ (24 meV),
La$_{2-2x}$Sr$_{1+2x}$Mn$_2$O$_7$ ($52-72$ meV), and Mn$_{90}$Cu$_{10}$ (88
meV). In addition, the spin-wave dispersion shows a deviation from the relation
$({\hbar\omega})^2 = c^2q^2 + {\Delta}^2$ above 40 meV. The group velocity
above this energy increases to 470(40) meV{\AA}, which is higher than that at
the low energies, $c = 226(5)$ meV{\AA}. These results could suggest that the
spin-wave excitations merge with the continuum of the individual particle-hole
excitations at 40 meV.


title:
Stochastic Primal-Dual Methods and Sample Complexity of Reinforcement
  Learning

abstract:
  We study the online estimation of the optimal policy of a Markov decision
process (MDP). We propose a class of Stochastic Primal-Dual (SPD) methods which
exploit the inherent minimax duality of Bellman equations. The SPD methods
update a few coordinates of the value and policy estimates as a new state
transition is observed. These methods use small storage and has low
computational complexity per iteration. The SPD methods find an
absolute-$\epsilon$-optimal policy, with high probability, using
$\mathcal{O}\left(\frac{|\mathcal{S}|^4 |\mathcal{A}|^2\sigma^2
}{(1-\gamma)^6\epsilon^2} \right)$ iterations/samples for the infinite-horizon
discounted-reward MDP and $\mathcal{O}\left(\frac{|\mathcal{S}|^4
|\mathcal{A}|^2H^6\sigma^2 }{\epsilon^2} \right)$ for the finite-horizon MDP.


title: EMP Lasing from Mn doped lead bromide perovskites nanorods

abstract:
  Diluted magnetic semiconductor (DMS) nanostructures are promising platform to
modulate carriers and spins for new information devices. Here we report that
the high quality pure CH3NH3PbBr3 nanorods and Mn doped CH3NH3PbBr3 nanorods
have been prepared by solution method and in which the exciton magnetic
polarons (EMP) formed in Mn doped NRs, and a single mode lasing phenomenon from
collective EMP in single NR have been detected when excited by fs pulse laser.
This finding helps to understand the exciton and spin interactions and pave
ways to the realization of new type of bosonic laser.


title: Global geometry on moduli of local systems for surfaces with boundary

abstract:
  We show that every coarse moduli space, parametrizing complex special linear
rank two local systems with fixed boundary traces on a surface with nonempty
boundary, is log Calabi-Yau in that it has a normal projective compactification
with trivial log canonical divisor. We connect this to a novel symmetry of
generating series for counts of essential multicurves on the surface.


title:
Moment Relaxations of Optimal Power Flow Problems: Beyond the Convex
  Hull

abstract:
  Optimal power flow (OPF) is one of the key electric power system optimization
problems. "Moment" relaxations from the Lasserre hierarchy for polynomial
optimization globally solve many OPF problems. Previous work illustrates the
ability of higher-order moment relaxations to approach the convex hulls of OPF
problems' non-convex feasible spaces. Using a small test case, this paper
focuses on the ability of the moment relaxations to globally solve problems
with objective functions that have unconstrained minima at infeasible points
inside the convex hull of the non-convex constraints.


title:
Full-gap superconductivity in non-centrosymmetric Re$_6$Zr,
  Re$_{27}$Zr$_{5}$ and Re$_{24}$Zr$_{5}$

abstract:
  Non-centrosymmetric superconductor Re$_6$Zr has attracted much interest, for
its possible unconventional superconducting state with time reversal symmetry
broken. Here we report the $^{185/187}$Re nuclear quadrupole resonance (NQR)
measurements on Re$_6$Zr ($T_c$ = 6.72 K) and the isostructural compounds
Re$_{27}$Zr$_{5}$ ($T_c$ = 6.53 K) and Re$_{24}$Zr$_{5}$ ($T_c$ = 5.00 K). The
nuclear spin-lattice relaxation rate $1/T_1$ shows a coherence peak below $T_c$
and decreases exponentially at low temperatures in all three samples. The
superconducting gap $\Delta$ derived from the $1/T_1$ data is $2\Delta =3.58 $
$k_BT_c$, 3.55 $k_BT_c$, and 3.51 $k_BT_c$ for Re$_6$Zr ,Re$_{27}$Zr$_{5}$, and
Re$_{24}$Zr$_{5}$, respectively, which is close to the value of 3.53 $k_BT_c$
expected for weak-coupling superconductivity. These data suggest conventional
$s$-wave superconductivity with a fully-opened gap in this series of compounds.


title:
An Efficient Algorithm for the Piecewise-Smooth Model with Approximately
  Explicit Solutions

abstract:
  This paper presents an efficient approach to image segmentation that
approximates the piecewise-smooth (PS) functional in [12] with explicit
solutions. By rendering some rational constraints on the initial conditions and
the final solutions of the PS functional, we propose two novel formulations
which can be approximated to be the explicit solutions of the evolution partial
differential equations (PDEs) of the PS model, in which only one PDE needs to
be solved efficiently. Furthermore, an energy term that regularizes the level
set function to be a signed distance function is incorporated into our
evolution formulation, and the time-consuming re-initialization is avoided.
Experiments on synthetic and real images show that our method is more efficient
than both the PS model and the local binary fitting (LBF) model [4], while
having similar segmentation accuracy as the LBF model.


title: Geometric Decomposition of Feed Forward Neural Networks

abstract:
  There have been several attempts to mathematically understand neural networks
and many more from biological and computational perspectives. The field has
exploded in the last decade, yet neural networks are still treated much like a
black box. In this work we describe a structure that is inherent to a feed
forward neural network. This will provide a framework for future work on neural
networks to improve training algorithms, compute the homology of the network,
and other applications. Our approach takes a more geometric point of view and
is unlike other attempts to mathematically understand neural networks that rely
on a functional perspective.


title: A Mini-Course on Stochastic Control

abstract:
  This note is addressed to giving a short introduction to control theory of
stochastic systems, governed by stochastic differential equations in both
finite and infinite dimensions. We will mainly explain the new phenomenon and
difficulties in the study of controllability and optimal control problems for
these sort of equations. In particular, we will show by some examples that both
the formulation of stochastic control problems and the tools to solve them may
differ considerably from their deterministic counterpart.


title: Nonlocality as a consequence of complementarity

abstract:
  Complementarity and nonlocality are two characteristic traits of quantum
physics that distinguishes it from classical physics. In this paper, we prove
that the complementarity between global and local observables in Bell's
experiment sets the decisive foundation for the nonlocality of composite
systems.


title: A novel regime for the dynamical Casimir effect

abstract:
  The dynamical Casimir effect (DCE) is the production of photons by the
amplification of vacuum fluctuations. In this paper we demonstrate new
resonance conditions in DCE that potentially allow the production of optical
photons when the mechanical frequency is smaller than the lowest frequency of
the cavity field. We consider a cavity with one mirror fixed and the other
allowed to oscillate. In order to identify the region where production of
photons takes place, we do a linear stability analysis and investigate the
dynamic stability of the system under small fluctuations. By using a numerical
solution of the Heisenberg equations of motion, the time evolution of the
number of photons produced in the unstable region is studied.


title: Prediction with a Short Memory

abstract:
  We consider the problem of predicting the next observation given a sequence
of past observations, and consider the extent to which accurate prediction
requires complex algorithms that explicitly leverage long-range dependencies.
Perhaps surprisingly, our positive results show that for a broad class of
sequences, there is an algorithm that predicts well on average, and bases its
predictions only on the most recent few observation together with a set of
simple summary statistics of the past observations. Specifically, we show that
for any distribution over observations, if the mutual information between past
observations and future observations is upper bounded by $I$, then a simple
Markov model over the most recent $I/\epsilon$ observations obtains expected KL
error $\epsilon$---and hence $\ell_1$ error $\sqrt{\epsilon}$---with respect to
the optimal predictor that has access to the entire past and knows the data
generating distribution. For a Hidden Markov Model with $n$ hidden states, $I$
is bounded by $\log n$, a quantity that does not depend on the mixing time, and
we show that the trivial prediction algorithm based on the empirical
frequencies of length $O(\log n/\epsilon)$ windows of observations achieves
this error, provided the length of the sequence is $d^{\Omega(\log
n/\epsilon)}$, where $d$ is the size of the observation alphabet.
  We also establish that this result cannot be improved upon, even for the
class of HMMs, in the following two senses: First, for HMMs with $n$ hidden
states, a window length of $\log n/\epsilon$ is information-theoretically
necessary to achieve expected $\ell_1$ error $\sqrt{\epsilon}$. Second, the
$d^{\Theta(\log n/\epsilon)}$ samples required to estimate the Markov model for
an observation alphabet of size $d$ is necessary for any computationally
tractable learning algorithm, assuming the hardness of strongly refuting a
certain class of CSPs.


title: Modelling the Proliferation of Terrorism via Diffusion and Contagion

abstract:
  The proliferation of terrorism is a serious concern in national and
international security, as its spread is seen as an existential threat to
Western liberal democracies. Understanding and effectively modelling the spread
of terrorism provides useful insight into formulating effective responses. A
mathematical model capturing the theoretical constructs of contagion and
diffusion is constructed for explaining the spread of terrorist activity and
used to analyse data from the Global Terrorism Database from 2000--2016 for
Afghanistan, Iraq, and Israel.


title:
Smoothing Effects of Bagging: Von Mises Expansions of Bagged Statistical
  Functionals

abstract:
  Bagging is a device intended for reducing the prediction error of learning
algorithms. In its simplest form, bagging draws bootstrap samples from the
training sample, applies the learning algorithm to each bootstrap sample, and
then averages the resulting prediction rules.
  We extend the definition of bagging from statistics to statistical
functionals and study the von Mises expansion of bagged statistical
functionals. We show that the expansion is related to the Efron-Stein ANOVA
expansion of the raw (unbagged) functional. The basic observation is that a
bagged functional is always smooth in the sense that the von Mises expansion
exists and is finite of length 1 + resample size $M$. This holds even if the
raw functional is rough or unstable. The resample size $M$ acts as a smoothing
parameter, where a smaller $M$ means more smoothing.