title:
Many-body effects in nonlinear optical responses of 2D layered
  semiconductors

abstract:
  We performed ultrafast degenerate pump-probe spectroscopy on monolayer WSe2
near its exciton resonance. The observed differential reflectance signals
exhibit signatures of strong many-body interactions including the
exciton-exciton interaction and free carrier induced band gap renormalization.
The exciton-exciton interaction results in a resonance blue shift which lasts
for the exciton lifetime (several ps), while the band gap renormalization
manifests as a resonance red shift with several tens ps lifetime. Our model
based on the many-body interactions for the nonlinear optical susceptibility
fits well the experimental observations. The power dependence of the spectra
shows that with the increase of pump power, the exciton population increases
linearly and then saturates, while the free carrier density increases
superlinearly, implying that exciton Auger recombination could be the origin of
these free carriers. Our model demonstrates a simple but efficient method for
quantitatively analyzing the spectra, and indicates the important role of
Coulomb interactions in nonlinear optical responses of such 2D materials.


title:
A Thermodynamically consistent model of the post-translational Kai
  circadian clock

abstract:
  The principal pacemaker of the circadian clock of the cyanobacterium S.
elongatus is a protein phosphorylation cycle consisting of three proteins,
KaiA, KaiB and KaiC. KaiC forms a homohexamer, with each monomer consisting of
two domains, CI and CII. Both domains can bind and hydrolyze ATP, but only the
CII domain can be phosphorylated, at two residues, in a well-defined sequence.
While this system has been studied extensively, how the clock is driven
thermodynamically has remained elusive. Inspired by recent experimental
observations and building on ideas from previous mathematical models, we
present a new, thermodynamically consistent, statistical-mechanical model of
the clock. At its heart are two main ideas: i) ATP hydrolysis in the CI domain
provides the thermodynamic driving force for the clock, switching KaiC between
an active conformational state in which its phosphorylation level tends to rise
and an inactive one in which it tends to fall; ii) phosphorylation of the CII
domain provides the timer for the hydrolysis in the CI domain. The model also
naturally explains how KaiA, by acting as a nucleotide exchange factor, can
stimulate phosphorylation of KaiC, and how the differential affinity of KaiA
for the different KaiC phosphoforms generates the characteristic temporal order
of KaiC phosphorylation. As the phosphorylation level in the CII domain rises,
the release of ADP from CI slows down, making the inactive conformational state
of KaiC more stable. In the inactive state, KaiC binds KaiB, which not only
stabilizes this state further, but also leads to the sequestration of KaiA, and
hence to KaiC dephosphorylation. Using a dedicated kinetic Monte Carlo
algorithm, we show that the model can describe a wealth of experimental data.

categories: physics.bio-ph q-bio.MN q-bio.QM q-bio.SC


title:
Anisotropies in the linear polarization of vacancy photoluminescence in
  diamond induced by crystal rotations and strong magnetic fields

abstract:
  We study the linear polarization properties of the photoluminescence of the
neutral and negatively charged nitrogen vacancies and neutral vacancies in
diamond crystals as function of their symmetry and their response to strong
external magnetic fields. The linear polarization degree, which exceeds 10% at
room temperature, and rotation of the polarization plane of their zero-phonon
lines significantly depend on the crystal rotation around specific axes
demonstrating anisotropic angular evolutions. The sign of the polarization
plane rotation is changed periodically through the crystal rotation, which
indicates a switching between electron excited states of orthogonal linear
polarizations. At external magnetic fields of up to 10 T, the angular
dependences of the linear polarization degree experience a remarkable phase
shift. Moreover, the rotation of the linear polarization plane increases
linearly with rising magnetic field at 6 K and room temperature, for the
negatively charged nitrogen vacancies, which is attributed to magneto-optical
Faraday rotation.


title: Neighborhood reconstruction and cancellation of graphs

abstract:
  We connect two seemingly unrelated problems in graph theory.
  Any graph $G$ has an associated neighborhood multiset $\mathscr{N}(G)= \{N(x)
\mid x\in V(G)\}$ whose elements are precisely the open vertex-neighborhoods of
$G$. In general there exist non-isomorphic graphs $G$ and $H$ for which
$\mathscr{N}(G)=\mathscr{N}(H)$. The neighborhood reconstruction problem asks
the conditions under which $G$ is uniquely reconstructible from its
neighborhood multiset, that is, the conditions under which
$\mathscr{N}(G)=\mathscr{N}(H)$ implies $G\cong H$. Such a graph is said to be
neighborhood-reconstructible.
  The cancellation problem for the direct product of graphs seeks the
conditions under which $G\times K\cong H\times K$ implies $G\cong H$. Lovasz
proved that this is indeed the case if $K$ is not bipartite. A second instance
of the cancellation problem asks for conditions on $G$ that assure $G\times
K\cong H\times K$ implies $G\cong H$ for any bipartite graph $K$ with $E(K)\neq
\emptyset$. A graph $G$ for which this is true is called a cancellation graph.
  We prove that the neighborhood-reconstructible graphs are precisely the
cancellation graphs. We also present some new results on cancellation graphs,
which have corresponding implications for neighborhood reconstruction.


title:
Testing Higgs Coupling Precision and New Physics Scales at Lepton
  Colliders

abstract:
  The next-generation lepton colliders, such as CEPC, FCC-ee, and ILC will make
precision measurement of the Higgs boson properties. We first extract the Higgs
coupling precision from Higgs observables at CEPC to illustrate the potential
of future lepton colliders. Depending on the related event rates, the precision
can reach percentage level for most couplings. Then, we try to estimate the new
physics scales that can be indirectly probed with Higgs and electroweak
precision observables. The Higgs observables, together with the existing
electroweak precision observables, can probe new physics up to 10TeV (40TeV for
the gluon-related operator $\mathcal O_g$) at 95% C.L. Including the $Z/W$ mass
measurements and $Z$-pole observables at CEPC further pushes the limit up to
35TeV. Although $Z$-pole running is originally for the purpose of machine
calibration, it can be as important as the Higgs observables for probing the
new physics scales indirectly. The indirect probe of new physics scales at
lepton colliders can mainly cover the energy range to be explored by the
following hadron colliders of pp (50-100TeV), such as SPPC and FCC-hh.


title: A short proof of Rudnev's point-plane incidence bound

abstract:
  In this note we give a shortened proof of a theorem of Rudnev, which bounds
the number of incidences between points and planes over an arbitrary field.
Rudnev's proof uses a map that goes via the four-dimensional Klein quadric to a
three-dimensional space, where it applies a bound of Guth and Katz on
intersection points of lines. We describe a simple geometric map that directly
sends point-plane incidences to line-line intersections in space, allowing us
to reprove Rudnev's theorem with fewer technicalities.


title:
Creation and manipulation of stable dark solitons and vortices in
  microcavity polariton condensates

abstract:
  Solitons and vortices obtain widespread attention in different physical
systems as they offer potential use in information storage, processing, and
communication. In exciton-polariton condensates in semiconductor microcavities,
solitons and vortices can be created optically. However, dark solitons are
unstable and vortices cannot be spatially controlled. In the present work we
demonstrate the existence of stable dark solitons and vortices under
non-resonant incoherent excitation of a polariton condensate with a simple
spatially periodic pump. In one dimension, we show that an additional coherent
light pulse can be used to create or destroy a dark soliton in a controlled
manner. In two dimensions we demonstrate that a coherent light beam can be used
to move a vortex to a specific position on the lattice or be set into motion by
simply switching the periodic pump structure from two-dimensional (lattice) to
one-dimensional (stripes). Our theoretical results open up exciting
possibilities for optical on-demand generation and control of dark solitons and
vortices in polariton condensates.


title:
Flexible and compact hybrid metasurfaces for enhanced ultra high field
  in vivo magnetic resonance imaging

abstract:
  Developments in metamaterials and related structures such as metasurfaces
have opened up new possibilities in designing materials and devices with unique
properties. The main progress related to electromagnetic waves applications was
done in optical and microwave spectra. Here we report about a new hybrid
metasurface structure, comprising a two-dimensional metamaterial surface and a
very high permittivity dielectric substrate that was designed to enhance the
performance of an ultra-high field MRI scanner. This new flexible and compact
resonant structure is the first one which can be integrated into a
multi-element close-fitting receive coil array used for all clinical MRI. We
successfully demonstrated the operation of the metasurface in acquiring vivo
human brain images and spectra with enhanced local sensitivity on a commercial
7 Tesla system. These experimental findings prove the feasibility of real
clinical applications of metasurfaces in MRI.


title: Area bounds for minimal surfaces in geodesic ball of hyperbolic space

abstract:
  In hyperbolic space $H^n$ we set a geodesic ball of radius $\rho$. Consider a
$k$ dimensional minimal submanifold passing through the origin of the geodesic
ball with boundary lies on the boundary of that geodesic ball. We prove that
its area is no less than the totally geodesic $k$ dimensional submanifold
passing through the origin in that geodesic ball. This is a partial
generalization of the corresponding problem in $R^n$.


title: The trace of the canonical module

abstract:
  The trace of the canonical module (the canonical trace) determines the
non-Gorenstein locus of a local Cohen--Macaulay ring. We call a local
Cohen--Macaulay ring nearly Gorenstein, if its canonical trace contains the
maximal ideal. Similar definitions can be made for positively graded
Cohen--Macaulay $K$-algebras. We study the canonical trace for tensor products
and Segre products of algebras, as well as of (squarefree) Veronese
subalgebras. The results are used to classify the nearly Gorenstein Hibi rings.
We study connections between the class of nearly Gorenstein rings and that of
almost Gorenstein rings. We show that in dimension one, the former class
includes the latter.


title: Elucidating the Voltage Controlled Magnetic Anisotropy

abstract:
  Voltage controlled magnetic anisotropy (VCMA) is an efficient way to
manipulate the magnetization states in nanomagnets, promising for low-power
spintronic applications. The underlying physical mechanism for VCMA is known to
involve a change in the d-orbital occupation on the transition metal interface
atoms with an applied electric field. However, a simple qualitative picture of
how this occupation controls the magnetocrystalline anisotropy (MCA) and even
why in certain cases the MCA has opposite sign still remains elusive. In this
paper, we exploit a simple model of orbital populations to elucidate a number
of features typical for the interface MCA and the effect of electric field on
it, for 3d transition metal thin films used in magnetic tunnel junctions. We
find that in all considered cases including the Fe (001) surface, clean
Fe1-xCox(001)/MgO interface and oxidized Fe(001)/MgO interface, the effects of
alloying and electric field enhance the MCA energy with electron depletion
which is largely explained by the occupancy of the minority-spin dxz,yz
orbitals. On the other hand, the hole doped Fe(001) exhibits an inverse VCMA,
where the MCA enhancement is achieved when electrons are accumulated at the Fe
(001)/MgO interface with applied electric field. In this regime we predict a
significantly enhanced VCMA which exceeds 1pJ/Vm. Realizing this regime
experimentally may be favorable for a practical purpose of voltage driven
magnetization reversal.


title:
An Empirical Fitting Method for Type Ia Supernova Light Curves. II.
  Estimating the First-Light Time and Rise Time

abstract:
  We investigate a new empirical fitting method for the optical light curves of
Type Ia supernovae (SNe~Ia) that is able to estimate the first-light time of
SNe~Ia, even when they are not discovered extremely early. With an improved
ability to estimate the time of first light for SNe Ia, we compute the rise
times for a sample of 56 well-observed SNe~Ia. We find rise times ranging from
10.5 to 20.5 days, with a mean of 16.0 days, and confirm that the rise time is
generally correlated with the decline rate $\Delta m_{15}(B)$, but with large
scatter. The rise time could be an additional parameter to help classify SN~Ia
subtypes.


title:
Inverse scattering transform for the nonlocal nonlinear Schr\"{o}dinger
  equation with nonzero boundary conditions

abstract:
  In 2013 a new nonlocal symmetry reduction of the well-known AKNS scattering
problem was found; it was shown to give rise to a new nonlocal $PT$ symmetric
and integrable Hamiltonian nonlinear Schr\"{o}dinger (NLS) equation.
Subsequently, the inverse scattering transform was constructed for the case of
rapidly decaying initial data and a family of spatially localized, time
periodic one soliton solution were found. In this paper, the inverse scattering
transform for the nonlocal NLS equation with nonzero boundary conditions at
infinity is presented in the four cases when the data at infinity have constant
amplitudes. The direct and inverse scattering problems are analyzed.
Specifically, the direct problem is formulated, the analytic properties of the
eigenfunctions and scattering data and their symmetries are obtained. The
inverse scattering problem is developed via a left-right Riemann-Hilbert
problem in terms of a suitable uniformization variable and the time dependence
of the scattering data is obtained. This leads to a method to linearize/solve
the Cauchy problem. Pure soliton solutions are discussed and explicit 1-soliton
solution and two 2-soliton solutions are provided for three of the four
different cases corresponding to two different signs of nonlinearity and two
different values of the phase difference between plus and minus infinity. In
the one other case there are no solitons.


title: Fundamental theorem of Algebra - A Nevanlinna theoretic proof

abstract:
  There are several proofs of the Fundamental Theorem of Algebra, mainly using
algebra, analysis and topology. In this article, we have shown that the
Fundamental Theorem of Algebra can be proved using Nevanlinna's first
fundamental theorem as well as second fundamental theorem also.


title: Sterile neutrino searches at future $e^-e^+$, $pp$, and $e^-p$ colliders

abstract:
  Sterile neutrinos are among the most attractive extensions of the SM to
generate the light neutrino masses observed in neutrino oscillation
experiments. When the sterile neutrinos are subject to a protective symmetry,
they can have masses around the electroweak scale and potentially large
neutrino Yukawa couplings, which makes them testable at planned future particle
colliders. We systematically discuss the production and decay channels at
electron-positron, proton-proton and electron-proton colliders and provide a
complete list of the leading order signatures for sterile neutrino searches.
Among other things, we discuss several novel search channels, and present a
first look at the possible sensitivities for the active-sterile mixings and the
heavy neutrino masses. We compare the performance of the different collider
types and discuss their complementarity.


title:
Smoothness and Poisson structures of Bridgeland moduli spaces on Poisson
  surfaces

abstract:
  Let X be a projective smooth holomorphic Poisson surface, in other words,
whose anti-canonical divisor is effective. We show that moduli spaces of
certain Bridgeland stable objects on X are smooth. Moreover, we construct
Poisson structures on these moduli spaces.


title:
Higher-order Weierstrass weights of branch points on superelliptic
  curves

abstract:
  In this paper we consider the problem of calculating the higher-order
Weierstrass weight of the branch points of a superelliptic curve $C$. For any
$q>1$, we give an exact formula for the $q$-weight of an affine branch point.
We also find a formula for the $q$-weight of a point at infinity in the case
where $n$ and $d$ are relatively prime. With these formulas, for any fixed $n$,
we obtain an asymptotic formula for the ratio of the $q$-weight of the branch
points, denoted $BW_q$, to the total $q$-weight of points on the curve: \[
\liminf_{d\to\infty}\frac{BW_q}{g(g-1)^2(2q-1)^2}\geq
\frac{n+1}{3(n-1)^2(2q-1)^2},\] with equality when the limit is taken such that
$\gcd(n,d)=1$.


title:
Automatic Differentiation: a look through Tensor and Operational
  Calculus

abstract:
  In this paper we take a look at Automatic Differentiation through the eyes of
Tensor and Operational Calculus. This work is best consumed as supplementary
material for learning tensor and operational calculus by those already familiar
with automatic differentiation. To that purpose, we provide a simple
implementation of automatic differentiation, where the steps taken are
explained in the language tensor and operational calculus.


title:
TCP-aware Cross Layer Scheduling with Adaptive Modulation in IEEE 802.16
  (WiMAX) Networks

abstract:
  In this paper, we propose Transmission Control Protocol (TCP)-aware cross
layer scheduling algorithms in a multipoint-to-point network such as the uplink
of an IEEE 802.16 (WiMAX) network. Inadequate bandwidth allocation to a TCP
flow may lead to timeout and since TCP source drops its congestion window
($cwnd$) immediately after a timeout, it may affect the average throughput
adversely. On the other hand, since the TCP source increases its $cwnd$ only
linearly upon the availability of bandwidth, any excess assignment of bandwidth
may remain underutilized. The proposed scheduling algorithms address this by
allocating the resources based on $cwnd$ and TCP timeout. Moreover, since we
focus on uplink scheduling, we consider that only {\em flow} level resource
requirement is communicated to the Base Station ($BS$) instead of per {\em
packet} information. The schedulers also take into account the wireless channel
characteristics and are thus cross layer in nature. Through exhaustive
simulations, we demonstrate that the proposed schedulers exhibit enhanced
throughput and fairness properties when compared to that of Round Robin (RR)
scheduler under different shadowing. We demonstrate a gain between 3.5 \% to 15
\% in throughput and 15 \% to 25 \% in channel utilization over RR scheduler
under different shadowing.


title: Regular Dilation on Graph Products of $\mathbb{N}$

abstract:
  We extended the definition of regular dilation to graph products of
$\mathbb{N}$, which is an important class of quasi-lattice ordered semigroups.
Two important results in dilation theory are unified under our result: namely,
Brehmer's regular dilation on $\mathbb{N}^k$ and Frazho-Bunce-Popescu's
dilation of row contractions. We further show that a representation of a graph
product has an isometric Nica-covariant dilation if and only if it is
$\ast$-regular. A special case of our result was considered by Popescu, and we
studied the connection with Popescu's work.


title:
Learning in the Machine: Random Backpropagation and the Deep Learning
  Channel

abstract:
  Random backpropagation (RBP) is a variant of the backpropagation algorithm
for training neural networks, where the transpose of the forward matrices are
replaced by fixed random matrices in the calculation of the weight updates. It
is remarkable both because of its effectiveness, in spite of using random
matrices to communicate error information, and because it completely removes
the taxing requirement of maintaining symmetric weights in a physical neural
system. To better understand random backpropagation, we first connect it to the
notions of local learning and learning channels. Through this connection, we
derive several alternatives to RBP, including skipped RBP (SRPB), adaptive RBP
(ARBP), sparse RBP, and their combinations (e.g. ASRBP) and analyze their
computational complexity. We then study their behavior through simulations
using the MNIST and CIFAR-10 bechnmark datasets. These simulations show that
most of these variants work robustly, almost as well as backpropagation, and
that multiplication by the derivatives of the activation functions is
important. As a follow-up, we study also the low-end of the number of bits
required to communicate error information over the learning channel. We then
provide partial intuitive explanations for some of the remarkable properties of
RBP and its variations. Finally, we prove several mathematical results,
including the convergence to fixed points of linear chains of arbitrary length,
the convergence to fixed points of linear autoencoders with decorrelated data,
the long-term existence of solutions for linear systems with a single hidden
layer and convergence in special cases, and the convergence to fixed points of
non-linear chains, when the derivative of the activation functions is included.


title:
Harmonic analysis approach to Gromov--Hausdorff convergence for
  noncommutative tori

abstract:
  We show that the rotation algebras are limit of matrix algebras in a very
strong sense of convergence for algebras with additional Lipschitz structure.
Our results generalize to higher dimensional noncommutative tori and operator
valued coefficients. In contrast to previous results by Rieffel, Li, Kerr, and
Latr\'emoli\`ere we use Lipschitz norms induced by the `carr\'e du champ' of
certain natural dynamical systems, including the heat semigroup.


title:
An accelerated Poisson solver based on multidomain spectral
  discretization

abstract:
  This paper presents a numerical method for variable coefficient elliptic PDEs
with mostly smooth solutions on two dimensional domains. The PDE is discretized
via a multi-domain spectral collocation method of high local order (order 30
and higher have been tested and work well). Local mesh refinement results in
highly accurate solutions even in the presence of local irregular behavior due
to corner singularities, localized loads, etc. The system of linear equations
attained upon discretization is solved using a direct (as opposed to iterative)
solver with $O(N^{1.5})$ complexity for the factorization stage and $O(N \log
N)$ complexity for the solve. The scheme is ideally suited for executing the
elliptic solve required when parabolic problems are discretized via
time-implicit techniques. In situations where the geometry remains unchanged
between time-steps, very fast execution speeds are obtained since the solution
operator for each implicit solve can be pre-computed.


title: A-infinity resolutions and the Golod property for monomial rings

abstract:
  Let R=S/I be a monomial ring whose minimal free resolution F is rooted. We
describe an A-infinity algebra structure on F. Using this structure, we show
that R is Golod if and only if the product on Tor^S(R,k) vanishes. Furthermore,
we give a necessary and sufficient combinatorial condition for R to be Golod.


title: Global behavior of solutions to generalized Gross-Pitaevskii equation

abstract:
  This paper is concerned with time global behavior of solutions to nonlinear
Schr\"odinger equation with a non-vanishing condition at the spatial infinity.
Under a non-vanishing condition, it would be expected that the behavior is
determined by the shape of the nonlinear term around the non-vanishing state.
To observe this phenomenon, we introduce a generalized version of the
Gross-Pitaevskii equation, which is a typical equation involving a
non-vanishing condition, by modifying the shape of nonlinearity around the
non-vanishing state. It turns out that, if the nonlinearity decays fast as a
solution approaches to the non-vanishing state, then the equation admits a
global solution which scatters to the non-vanishing element for both time
directions.


title: Controlling Robot Morphology from Incomplete Measurements

abstract:
  Mobile robots with complex morphology are essential for traversing rough
terrains in Urban Search & Rescue missions (USAR). Since teleoperation of the
complex morphology causes high cognitive load of the operator, the morphology
is controlled autonomously. The autonomous control measures the robot state and
surrounding terrain which is usually only partially observable, and thus the
data are often incomplete. We marginalize the control over the missing
measurements and evaluate an explicit safety condition. If the safety condition
is violated, tactile terrain exploration by the body-mounted robotic arm
gathers the missing data.


title:
3D Radiation Non-ideal Magnetohydrodynamical Simulations Of The Inner
  Rim In Protoplanetary Disks

abstract:
  Many planets orbit within an AU of their stars, raising questions about their
origins. Particularly puzzling are the planets found near the silicate
sublimation front. We investigate conditions near the front in the protostellar
disk around a young intermediate-mass star, using the first global 3-D
radiation non-ideal MHD simulations in this context. We treat the starlight
heating; the silicate grains sublimation and deposition at the local,
time-varying temperature and density; temperature-dependent Ohmic dissipation;
and various initial magnetic fields. The results show magnetorotational
turbulence around the sublimation front at 0.5 AU. The disk interior to 0.8 AU
is turbulent, with velocities exceeding 10% of the sound speed. Beyond 0.8 AU
is the dead zone, cooler than 1000 K and with turbulence orders of magnitude
weaker. A local pressure maximum just inside the dead zone concentrates solid
particles, favoring their growth. Over many orbits, a vortex develops at the
dead zones inner edge, increasing the disks thickness locally by around 10%. We
synthetically observe the results using Monte Carlo transfer calculations,
finding the sublimation front is near-infrared bright. The models with net
vertical magnetic fields develop extended, magnetically-supported atmospheres
that reprocess extra starlight, raising the near-infrared flux 20%.The vortex
throws a nonaxisymmetric shadow on the outer disk. At wavelengths > 2 micron,
the flux varies several percent on monthly timescales. The variations are more
regular when the vortex is present. The vortex is directly visible as an arc at
ultraviolet through near-infrared wavelengths, given sub-AU spatial resolution.


title: Coupling Distributed and Symbolic Execution for Natural Language Queries

abstract:
  Building neural networks to query a knowledge base (a table) with natural
language is an emerging research topic in deep learning. An executor for table
querying typically requires multiple steps of execution because queries may
have complicated structures. In previous studies, researchers have developed
either fully distributed executors or symbolic executors for table querying. A
distributed executor can be trained in an end-to-end fashion, but is weak in
terms of execution efficiency and explicit interpretability. A symbolic
executor is efficient in execution, but is very difficult to train especially
at initial stages. In this paper, we propose to couple distributed and symbolic
execution for natural language queries, where the symbolic executor is
pretrained with the distributed executor's intermediate execution results in a
step-by-step fashion. Experiments show that our approach significantly
outperforms both distributed and symbolic executors, exhibiting high accuracy,
high learning efficiency, high execution efficiency, and high interpretability.


title: Joint Hand Detection and Rotation Estimation by Using CNN

abstract:
  Hand detection is essential for many hand related tasks, e.g. parsing hand
pose, understanding gesture, which are extremely useful for robotics and
human-computer interaction. However, hand detection in uncontrolled
environments is challenging due to the flexibility of wrist joint and cluttered
background. We propose a deep learning based approach which detects hands and
calibrates in-plane rotation under supervision at the same time. To guarantee
the recall, we propose a context aware proposal generation algorithm which
significantly outperforms the selective search. We then design a convolutional
neural network(CNN) which handles object rotation explicitly to jointly solve
the object detection and rotation estimation tasks. Experiments show that our
method achieves better results than state-of-the-art detection models on
widely-used benchmarks such as Oxford and Egohands database. We further show
that rotation estimation and classification can mutually benefit each other.


title: Update of the Hadronic Vacuum Polarisation Contribution to the muon g-2

abstract:
  Precise data on e^+e^- to hadrons have recently become available and are used
to compute the lowest-order hadronic vacuum polarisation contribution to the
muon magnetic anomaly through dispersion relations. This is the case for the
dominant pi+ pi- channel, but the most significant progress comes from the near
completion of the BABAR program of measuring exclusive processes below 2 GeV
with the initial-state radiation method which allows an efficient coverage of a
large range of energies.. In this paper we briefly review the data treatment,
the achieved improvements, and the result obtained for the full Standard Model
prediction of the muon magnetic anomaly. The value obtained, a_mu
(had~LO)=(692.6 +- 3.3)x 10^{-10} is 20% more precise than our last estimate in
2010. It deviates from the direct experimental determination by (27.4 +- 7.6)x
10^{-10} (3.6 sigma). Perpectives for further improvement are discussed.


title:
Ionic Coulomb blockade and anomalous mole fraction effect in NaChBac
  bacterial ion channels

abstract:
  We report an experimental study of the influences of the fixed charge and
bulk ionic concentrations on the conduction of biological ion channels, and we
consider the results within the framework of the ionic Coulomb blockade model
of permeation and selectivity. Voltage clamp recordings were used to
investigate the Na$^+$/Ca$^{2+}$ anomalous mole fraction effect (AMFE)
exhibited by the bacterial sodium channel NaChBac and its mutants.
Site-directed mutagenesis was used to study the effect of either increasing or
decreasing the fixed charge in their selectivity filters for comparison with
the predictions of the Coulomb blockade model. The model was found to describe
well some aspects of the experimental (divalent blockade and AMFE) and
simulated (discrete multi-ion conduction and occupancy band) phenomena,
including a concentration-dependent shift of the Coulomb staircase. These
results substantially extend the understanding of ion channel selectivity and
may also be applicable to biomimetic nanopores with charged walls.


title: Instantaneously complete Yamabe flow on hyperbolic space

abstract:
  We prove global existence of instantaneously complete Yamabe flows on
hyperbolic space of arbitrary dimension $m\geq3$. The initial metric is assumed
to be conformally hyperbolic with conformal factor and scalar curvature bounded
from above. We do not require initial completeness or bounds on the Ricci
curvature. If the initial data are rotationally symmetric, the solution is
proven to be unique in the class of instantaneously complete, rotationally
symmetric Yamabe flows.


title:
Potential reduction interior point algorithm unfolding of neutron energy
  spectrum measured by recoil proton method

abstract:
  A reconstruction algorithm for unfolding the neutron energy spectrum has been
developed based on the potential reduction interior point. This algorithm can
be easily applied to the neutron energy spectrum reconstruction in the recoil
proton method. We transform neutron energy spectrum unfolding problem into a
typical nonnegative linear complementarity problem. The recoil proton energy
spectrum and response matrix at angles of 0{\deg} and 30{\deg} are generated by
the Geant4 simulation toolkit. Several different neutron energy test spectrums
are also employed. It is found that this unfolding algorithm is stable and
provide efficiency accurate results.


title: An approach to the topological complexity of the Klein bottle

abstract:
  Recently, Cohen and Vandembroucq proved that the reduced topological
complexity of the Klein bottle is 4. Simultaneously and independently, we
announced a proof of the same result. Mistakes were found in our argument,
which was quite different than theirs. After correcting these, we found that
our description of the obstruction class agreed with theirs. Our approach to
showing that this obstruction is nonzero failed to do so, while theirs did not
fail. Here we discuss our approach, which deals more directly with the
simplicial structure of the Klein bottle.


title: Two-dimensional ReN$_2$ materials from first principles

abstract:
  The discovery of graphene makes it highly desirable to seek new
two-dimensional materials. Through first-principles investigation, we predict
two-dimensional materials of ReN$_{2}$: honeycomb and tetragonal structures.
The phonon spectra establish the dynamical stability for both of the two
structures, and the calculated in-plane stiffness constants proves their
mechanical stability. The energy bands near the Fermi level consist of N-p and
Re-d orbitals for the honeycomb structure, and are mainly from Re d orbitals
for the tetragonal structure. While the tetragonal structure is non-magnetic,
the honeycomb structure has N-based ferromagnetism, which will transit to
anti-ferromagnetism under 14$\%$ biaxial strain. The calculated electron
localization function and spin density indicate that direct N-N bond can occur
only in the honeycomb structure. The ferromagnetism allows us to distinguish
the two 2D phases easily. The tetragonal phase has lower energy than the
honeycomb one, which means that the tetragonal phase is more stable, but the
hexagonal phase has much larger bulk, shear, and Young's muduli than the
tetragonal phase. The tetragonal phase is a three-bands metal, and the
hexagonal phase is a ferromagnetic semi-metal. The special structural,
electronic, magnetic, and optical properties in the honeycomb and tetragonal
structures make them promising for novel applications.


title: Adaptive mesh point selection for the efficient solution of scalar IVPs

abstract:
  We discuss adaptive mesh point selection for the solution of scalar IVPs. We
consider a method that is optimal in the sense of the speed of convergence, and
aim at minimizing the local errors. Although the speed of convergence cannot be
improved by using the adaptive mesh points compared to the equidistant points,
we show that the factor in the error expression can be significantly reduced.
We obtain formulas specifying the gain achieved in terms of the number of
discretization subintervals, as well as in terms of the prescribed level of the
local error. Both nonconstructive and constructive versions of the adaptive
mesh selection are shown, and a numerical example is given.


title: QEX: a framework for lattice field theories

abstract:
  We present a new software framework for simulating lattice field theories. It
features an intuitive programming interface, while simultaneously achieving
high performance supercomputing, all in one programming language, Nim. With a
macro system based on its abstract syntax tree, the language enables us to
check and optimize our code at compile time. It also allows us to code
intrinsics that map directly to machine instructions, and generates efficient
native code. We show how we use Nim's metaprogramming features in our code, and
present the current status of the code and future plans.


title: Protein-Ligand Scoring with Convolutional Neural Networks

abstract:
  Computational approaches to drug discovery can reduce the time and cost
associated with experimental assays and enable the screening of novel
chemotypes. Structure-based drug design methods rely on scoring functions to
rank and predict binding affinities and poses. The ever-expanding amount of
protein-ligand binding and structural data enables the use of deep machine
learning techniques for protein-ligand scoring.
  We describe convolutional neural network (CNN) scoring functions that take as
input a comprehensive 3D representation of a protein-ligand interaction. A CNN
scoring function automatically learns the key features of protein-ligand
interactions that correlate with binding. We train and optimize our CNN scoring
functions to discriminate between correct and incorrect binding poses and known
binders and non-binders. We find that our CNN scoring function outperforms the
AutoDock Vina scoring function when ranking poses both for pose prediction and
virtual screening.


title:
Phase segregation facilitates exfoliation of franckeite crystals to a
  single unit cell thickness

abstract:
  Weak interlayer van der Waals interactions in bulk crystals facilitate their
mechanical exfoliation to monolayer and few-layer two-dimensional (2D)
materials, which exhibit striking physical phenomena absent in their bulk form.
Here we study a 2D form of a mineral franckeite and show that phase segregation
into discrete layers at the sub-nanometre scale facilitates its layered
structure and basal cleavage. This behaviour is likely to be common in a wider
family of complex crystals and could be exploited for a single-step synthesis
of van der Waals heterostructures, as an alternative to stacking of 2D
materials. Mechanical exfoliation allowed us to produce crystals down to a
single unit cell thickness and rationalise its basal cleavage by
atomic-resolution scanning transmission electron microscopy (STEM). We
demonstrate p-type electrical conductivity and remarkable electrochemical
properties in exfoliated crystals, which shows promise for energy storage
applications.


title:
Integrability via geometry: dispersionless differential equations in
  three and four dimensions

abstract:
  We prove that the existence of a dispersionless Lax pair with spectral
parameter for a nondegenerate hyperbolic second order partial differential
equation (PDE) is equivalent to the canonical conformal structure defined by
the symbol being Einstein-Weyl on any solution in 3D, and self-dual on any
solution in 4D. The first main ingredient in the proof is a characteristic
property for dispersionless Lax pairs. The second is the projective behaviour
of the Lax pair with respect to the spectral parameter. Both are established
for nondegenerate determined systems of PDEs of any order. Thus our main result
applies more generally to any such PDE system whose characteristic variety is a
quadric hypersurface.


title:
On the non-equivalence of the Bernoulli and K properties in dimension
  four

abstract:
  We study skew products where the base is a hyperbolic automorphism of
$\mathbb{T}^2$, the fiber is a smooth area preserving flow on $\mathbb{T}^2$
with one fixed point (of high degeneracy) and the skewing function is a smooth
non coboundary with non-zero integral. The fiber dynamics can be represented as
a special flow over an irrational rotation and a roof function with one power
singularity. We show that for a full measure set of rotations the corresponding
skew product is $K$ and not Bernoulli. As a consequence we get a natural class
of volume-preserving diffeomorphisms of $\mathbb{T}^4$ which are $K$ and not
Bernoulli.


title:
Negative thermal expansion and local lattice distortion in the
  (Sc1-xTix)F3 and related solid solutions

abstract:
  Negative thermal expansion (NTE) is unusual but important property for
control of thermal expansion. In the present study, the chemical modification
is utilized to engineer controllable thermal expansion in cubic NTE ScF3. A
broad window of the coefficient of thermal expansion (CTE = -1.51 ~ -3.4*10^-6
K-1, 300-800 K) has been achieved in Sc1-xMxF3 (M = Ti, Al and Ga). The
long-range crystallographic structure of (Sc1-xTix)F3 adheres to the cubic
Pm-3m symmetry according to the analysis of high-energy synchrotron X-ray
powder diffraction. Pair distribution function (PDF) analysis of synchrotron
X-ray total scattering was performed to investigate the local lattice
distortion. It was found that the weakness of NTE has a close correlation with
the local lattice distortion. Based on the coupled rotation model, it is
presumably that this local distortion might dampen the transverse vibration of
F atoms and thus reduce NTE. The present work provides a possible reference for
the design of controllable NTE in open framework solids.


title: Smoothed Projections over Weakly Lipschitz Domains

abstract:
  We develop finite element exterior calculus over weakly Lipschitz domains.
Specifically, we construct commuting projections from $L^p$ de~Rham complexes
over weakly Lipschitz domains onto finite element de~Rham complexes. These
projections satisfy uniform bounds for finite element spaces with bounded
polynomial degree over shape-regular families of triangulations. Thus we extend
the theory of finite element differential forms to polyhedral domains that are
weakly Lipschitz but not strongly Lipschitz. As new mathematical tools, we use
the collar theorem in the Lipschitz category, and we show that the degrees of
freedom in finite element exterior calculus are flat chains in the sense of
geometric measure theory.


title:
Hierarchy through Composition with Linearly Solvable Markov Decision
  Processes

abstract:
  Hierarchical architectures are critical to the scalability of reinforcement
learning methods. Current hierarchical frameworks execute actions serially,
with macro-actions comprising sequences of primitive actions. We propose a
novel alternative to these control hierarchies based on concurrent execution of
many actions in parallel. Our scheme uses the concurrent compositionality
provided by the linearly solvable Markov decision process (LMDP) framework,
which naturally enables a learning agent to draw on several macro-actions
simultaneously to solve new tasks. We introduce the Multitask LMDP module,
which maintains a parallel distributed representation of tasks and may be
stacked to form deep hierarchies abstracted in space and time.


title:
Including heavy spin effects in the prediction of a $\bar{b} \bar{b} u
  d$ tetraquark with lattice QCD potentials

abstract:
  We investigate spin effects in four-quark systems consisting of two heavy
anti-bottom quarks and two light up/down quarks. To this end we use the
Born-Oppenheimer approximation. We utilize potentials of two static antiquarks
in the presence of two quarks of finite mass computed via lattice QCD and solve
a coupled-channel Schr\"odinger equation for the anti-bottom-anti-bottom
separation. Without taking heavy quark spins into account this approach
predicted a $u d \bar b \bar b$ tetraquark bound state with quantum numbers
$I(J^P) = 0(1^+)$. We now extend this Born-Oppenheimer approach with coupled
channel Schr\"odinger equations allowing us to incorporate effects due to the
heavy $\bar b$ spins. We confirm the existence of the $u d \bar b \bar b$
tetraquark.


title: The Galilean Superstring

abstract:
  The action for a Galilean superstring is found from a non-relativistic limit
of the closed Green-Schwarz (GS) superstring; it has zero tension and provides
an example of a massless super-Galilean system A Wess-Zumino term leads to a
topological central charge in the Galilean supersymmetry algebra, such that
unitarity requires a upper bound on the total momentum. This Galilean-invariant
bound, which is also implied by the classical phase-space constraints, is
saturated by solutions of the superstring equations of motion that
half-preserve supersymmetry. We discuss briefly the extension to the Galilean
supermembrane.


title:
Misiurewicz parameters and dynamical stability of polynomial-like maps
  of large topological degree

abstract:
  Given a family of polynomial-like maps of large topological degree, we relate
the presence of Misiurewicz parameters to a growth condition of the
postcritical volume. This allows us to generalize to this setting the theory of
stability and bifurcation developed by Berteloot, Dupont and the author for
endomorphisms of $\mathbb{P}^k$.


title:
A Maximum A Posteriori Estimation Framework for Robust High Dynamic
  Range Video Synthesis

abstract:
  High dynamic range (HDR) image synthesis from multiple low dynamic range
(LDR) exposures continues to be actively researched. The extension to HDR video
synthesis is a topic of significant current interest due to potential cost
benefits. For HDR video, a stiff practical challenge presents itself in the
form of accurate correspondence estimation of objects between video frames. In
particular, loss of data resulting from poor exposures and varying intensity
make conventional optical flow methods highly inaccurate. We avoid exact
correspondence estimation by proposing a statistical approach via maximum a
posterior (MAP) estimation, and under appropriate statistical assumptions and
choice of priors and models, we reduce it to an optimization problem of solving
for the foreground and background of the target frame. We obtain the background
through rank minimization and estimate the foreground via a novel multiscale
adaptive kernel regression technique, which implicitly captures local structure
and temporal motion by solving an unconstrained optimization problem. Extensive
experimental results on both real and synthetic datasets demonstrate that our
algorithm is more capable of delivering high-quality HDR videos than current
state-of-the-art methods, under both subjective and objective assessments.
Furthermore, a thorough complexity analysis reveals that our algorithm achieves
better complexity-performance trade-off than conventional methods.


title: String Diagrams For Double Categories and Equipments

abstract:
  A popular graphical calculus for monoidal categories makes computations
tactile and intuitive. Complicated diagram chases can be expressed in a few
pictures and discovered by playing with a shoelace. Joyal and Street's proof of
the soundness of this calculus says that any deformation of a diagram, any
bending of the strings, describes the same morphism. In this paper, we extend
the graphical calculus to double categories and proarrow equipments in order to
bring the string diagrammatic method to formal category theory. Our main
theorem proves this calculus sound with the help of Dawson and Pare's results
on composition in double categories.


title:
Computing the Bouligand derivative of a class of
  piecewise-differentiable flows

abstract:
  Event--selected $C^r$ vector fields yield piecewise-differentiable flows,
which possess a continuous and piecewise-linear Bouligand (or B-)derivative;
here we provide an algorithm for computing this B-derivative. The number of
"pieces" of the piecewise-linear B-derivative is factorial ($d!$) in the
dimension ($d$) of the space, precluding a polynomial-time algorithm. We show
how an exponential number ($2^d$) of points can be used to represent the
B-derivative as a piecewise-linear homeomorphism in such a way that evaluating
the derivative reduces to linear algebra computations involving a matrix
constructed from $d$ of these points.


title: Charged current neutrino interactions in hot and dense matter

abstract:
  We derive the charged current absorption rate of electron and anti-electron
neutrinos in dense matter using a fully relativistic approach valid at
arbitrary matter degeneracy. We include mean field energy shifts due to nuclear
interactions and the corrections due to weak magnetism. The rates are derived
both from the familiar Fermi's Golden Rule, and from the techniques of finite
temperature field theory, and shown to be equivalent. In various limits, these
results can also be used to calculate neutral current opacities. We find that
some pieces of the response have been left out in previous derivations and
their contribution at high density can be significant. Useful formulae and
detailed derivations are presented and we provide a new open source
implementation of these opacities for use in radiation hydrodynamic simulations
of core-collapse supernovae and neutron star mergers.


title: In-vacuo-dispersion features for GRB neutrinos and photons

abstract:
  Over the last 15 years there has been considerable interest in the
possibility of quantum-gravity-induced in-vacuo dispersion, the possibility
that spacetime itself might behave essentially like a dispersive medium for
particle propagation. Two very recent studies have exposed what might be
in-vacuo dispersion features for GRB (gamma-ray-burst) neutrinos of energy in
the range of 100 TeV and for GRB photons with energy in the range of 10 GeV. We
here show that these two features are roughly compatible with a description
such that the same effects apply over 4 orders of magnitude in energy. We also
characterize quantitatively how rare it would be for such features to arise
accidentally, as a result of (still unknown) aspects of the mechanisms
producing photons at GRBs or as a result of background neutrinos accidentally
fitting the profile of a GRB neutrino affected by in-vacuo dispersion.


title: Feedback Neural Network for Weakly Supervised Geo-Semantic Segmentation

abstract:
  Learning from weakly-supervised data is one of the main challenges in machine
learning and computer vision, especially for tasks such as image semantic
segmentation where labeling is extremely expensive and subjective. In this
paper, we propose a novel neural network architecture to perform
weakly-supervised learning by suppressing irrelevant neuron activations. It
localizes objects of interest by learning from image-level categorical labels
in an end-to-end manner. We apply this algorithm to a practical challenge of
transforming satellite images into a map of settlements and individual
buildings. Experimental results show that the proposed algorithm achieves
superior performance and efficiency when compared with various baseline models.


title:
Medium effects in ${\Lambda}K^+$ pair production by 2.83 GeV protons on
  nuclei

abstract:
  We study ${\Lambda}K^+$ pair production in the interaction of protons of 2.83
GeV kinetic energy with C, Cu, Ag, and Au target nuclei in the framework of the
nuclear spectral function approach for incoherent primary proton--nucleon and
secondary pion--nucleon production processes, and processes associated with the
creation of intermediate ${\Sigma^0}K^+$ pairs. The approach accounts for the
initial proton and final $\Lambda$ hyperon absorption, final $K^+$ meson
distortion in nuclei, target nucleon binding, and Fermi motion, as well as
nuclear mean-field potential effects on these processes. We calculate the
$\Lambda$ momentum dependence of the absolute ${\Lambda}K^+$ yield from the
target nuclei considered, in the kinematical conditions of the ANKE experiment,
performed at COSY, within the different scenarios for the $\Lambda$-nucleus
effective scalar potential. We show that the above observable is appreciably
sensitive to this potential in the low-momentum region. Therefore, direct
comparison of the results of our calculations with the data from the
ANKE-at-COSY experiment can help to determine the above potential at finite
momenta. We also demonstrate that the two-step pion--nucleon production
channels dominate in the low-momentum ${\Lambda}K^+$ production in the chosen
kinematics and, therefore, they have to be taken into account in the analysis
of these data.


title: X-ray flux variability of active galactic nuclei observed using NuSTAR

abstract:
  We present results on a systematic study of flux variability on hourly
time-scales in a large sample of active galactic nuclei (AGN) in the 3-79 keV
band using data from Nuclear Spectroscopic Telescope Array. Our sample consists
of 4 BL Lac objects (BL Lacs), 3 flat spectrum radio quasars (FSRQs) 24 Seyfert
1, 42 Seyfert 2 and 8 narrow line Seyfert 1 (NLSy1) galaxies. We find that in
the 3-79 keV band, about 65% of the sources in our sample show significant
variations on hourly time scales. Using Mann-Whitney U-test and
Kolmogorov-Smirnov test, we find no difference in the variability behaviour
between Seyfert 1 and 2 galaxies. The blazar sources (FSRQs and BL Lacs) in our
sample, are more variable than Seyfert galaxies that include Seyfert 1 and
Seyfert 2 in the soft (3-10 keV), hard (10-79 keV) and total (3-79 keV) bands.
NLSy1 galaxies show the highest duty cycle of variability (87%), followed by BL
Lacs (82%), Seyfert galaxies (56%) and FSRQs (23%). We obtained flux
doubling/halving time in the hard X-ray band less than 10 min in 11 sources.
The flux variations between the hard and soft bands in all the sources in our
sample are consistent with zero lag.


title:
Lorentz invariance violation and simultaneous emission of
  electromagnetic and gravitational waves

abstract:
  In this work, we compute some phenomenological bounds for the electromagnetic
and massive gravitational high-derivative extensions supposing that it is
possible to have an astrophysical process that generates simultaneously
gravitational and electromagnetic waves. We present Lorentz invariance
violating (LIV) higher-order derivative models, following the Myers-Pospelov
approach, to electrodynamics and massive gravitational waves. We compute the
corrected equation of motion of these models, their dispersion relations and
the velocities. The LIV parameters for the gravitational and electromagnetic
sectors, $\xi_{g}$ and $\xi_{\gamma}$, respectively, were also obtained for
three different approaches: luminal photons, time delay of flight and the
difference of graviton and photon velocities. These LIV parameters depend on
the mass scales where the LIV-terms become relevant, $M$ for the
electromagnetic sector and $M_{1}$ for the gravitational one. We obtain, using
the values for $M$ and $M_{1}$ found in the literature, that
$\xi_{g}\sim10^{-2}$, which is expected to be phenomenologically relevant and
$\xi_{\gamma}\sim10^{3}$, which cannot be suitable for an effective LIV theory.
However, we show that $\xi_{\gamma}$ can be interesting in a phenomenological
point of view if $M\gg M_{1}$. Finally the relation between the variation of
the velocities of the photon and the graviton in relation to the speed of light
was calculated and resulted in $\Delta v_{g}/\Delta
v_{\gamma}\lesssim1.82\times 10^{-3}$.


title: Autocatalytic Sets and RNA Secondary Structure

abstract:
  The dominant paradigm in origin of life research is that of an RNA world.
However, despite experimental progress towards the spontaneous formation of
RNA, the RNA world hypothesis still has its problems. Here, we introduce a
novel computational model of chemical reaction networks based on RNA secondary
structure and analyze the existence of autocatalytic sub-networks in random
instances of this model, by combining two well-established computational tools.
Our main results are that (i) autocatalytic sets are highly likely to exist,
even for very small reaction networks and short RNA sequences, and (ii)
sequence diversity seems to be a more important factor in the formation of
autocatalytic sets than sequence length. These findings could shed new light on
the probability of the spontaneous emergence of an RNA world as a network of
mutually collaborative ribozymes.


title: Probing the BFKL dynamics in inclusive three jet production at the LHC

abstract:
  We propose the study of new observables in LHC inclusive events with three
tagged jets, one in the forward direction, one in the backward direction and
both well-separated in rapidity from the each other (Mueller-Navelet jets),
together with a third jet tagged in central regions of rapidity. Since
non-tagged associated mini-jet multiplicity is allowed, we argue that
projecting the cross sections on azimuthal-angle components can provide several
distinct tests of the BFKL dynamics. Realistic LHC kinematical cuts are
introduced.


title: Chiral Tensors of Mixed Young Symmetry

abstract:
  Chiral tensors of mixed Young symmetry, which exist in the same spacetime
dimensions $2 + 4n$ where chiral $p$-forms can be defined, are investigated.
Such chiral tensors have been argued to play a central role in exotic
formulations of gravity in 6 dimensions and possess intriguing properties. A
variational principle that yields the chiral equations of motion is explicitly
constructed and related to the action for a non-chiral tensor. The use of
prepotentials turns out to be essential in our analysis. We also comment on
dimensional reduction.


title: Cohomology of Polychromatic Configuration Spaces of Euclidean Space

abstract:
  Recently, the homology and cohomology of non-k-overlapping discs, or,
equivalently, no k-equal subspaces of Euclidean space, were calculated by
Dobrinskaya and Turchin. We calculate the homology and cohomology of two
classes of more general spaces: decreasing polychromatic configuration spaces
and bicolored configuration spaces. Instead of all points behaving similarly,
we allow for varying behavior between points.


title: The distribution of radioactive $^{44}$Ti in Cassiopeia A

abstract:
  The distribution of elements produced in the inner-most layers of a supernova
explosion is a key diagnostic for studying the collapse of massive stars. Here
we present the results of a 2.4 Ms \textit{NuSTAR} observing campaign aimed at
studying the supernova remnant Cassiopeia A (Cas A). We perform
spatially-resolved spectroscopic analyses of the $^{44}$Ti ejecta which we use
to determine the Doppler shift and thus the three-dimensional (3D) velocities
of the $^{44}$Ti ejecta. We find an initial $^{44}$Ti mass of 1.54 $\pm$ 0.21
$\times 10^{-4}$ M$_{\odot}$ which has a present day average momentum direction
of 340$^{\circ}$ $\pm$ 15$^{\circ}$ projected on to the plane of the sky
(measured clockwise from Celestial North) and tilted by 58$^{\circ}$ $\pm$
20$^{\circ}$ into the plane of the sky away from the observer, roughly opposite
to the inferred direction of motion of the central compact object. We find some
$^{44}$Ti ejecta that are clearly interior to the reverse shock and some that
are clearly exterior to the reverse shock. Where we observe $^{44}$Ti ejecta
exterior to the reverse shock we also see shock-heated iron; however, there are
regions where we see iron but do not observe $^{44}$Ti. This suggests that the
local conditions of the supernova shock during explosive nucleosynthesis varied
enough to suppress the production of $^{44}$Ti in some regions by at least a
factor of two, even in regions that are assumed to be the result of processes
like $\alpha$-rich freezeout that should produce both iron and titanium.


title:
Continuum limit and stochastic homogenization of discrete ferromagnetic
  thin films

abstract:
  We study the discrete-to-continuum limit of ferromagnetic spin systems when
the lattice spacing tends to zero. We assume that the atoms are part of a
(maybe) non-periodic lattice close to a flat set in a lower dimensional space,
typically a plate in three dimensions. Scaling the particle positions by a
small parameter $\varepsilon>0$ we perform a $\Gamma$-convergence analysis of
properly rescaled interfacial-type energies. We show that, up to subsequences,
the energies converge to a surface integral defined on partitions of the flat
space. In the second part of the paper we address the issue of stochastic
homogenization in the case of random stationary lattices. A finer dependence of
the homogenized energy on the average thickness of the random lattice is
analyzed for an example of magnetic thin system obtained by a random deposition
mechanism.


title:
Discovery of XO-6b: a hot Jupiter transiting a fast rotating F5 star on
  an oblique orbit

abstract:
  Only a few hot Jupiters are known to orbit around fast rotating stars. These
exoplanets are harder to detect and characterize and may be less common than
around slow rotators. Here, we report the discovery of the transiting hot
Jupiter XO-6b, which orbits a bright, hot, and fast rotating star: V = 10.25,
Teff = 6720 +/- 100 K, v sin i = 48 +/- 3 km/s. We detected the planet from its
transits using the XO instruments and conducted a follow-up campaign. Because
of the fast stellar rotation, radial velocities taken along the orbit do not
yield the planet's mass with a high confidence level, but we secure a 3-sigma
upper limit Mp < 4.4 MJup. We also obtain high resolution spectroscopic
observations of the transit with the SOPHIE spectrograph at the 193-cm
telescope of the Observatoire de Haute-Provence and analyze the stellar lines
profile by Doppler tomography. The transit is clearly detected in the spectra.
The radii measured independently from the tomographic analysis and from the
photometric lightcurves are consistent, showing that the object detected by
both methods is the same and indeed transits in front of XO-6. We find that
XO-6b lies on a prograde and misaligned orbit with a sky-projected obliquity
lambda = -20.7 +/- 2.3 deg. The rotation period of the star is shorter than the
orbital period of the planet: Prot < 2.12 days, Porb = 3.77 days. Thus, this
system stands in a largely unexplored regime of dynamical interactions between
close-in giant planets and their host stars.


title: Inverse Electromagnetic Diffraction by Biperiodic Dielectric Gratings

abstract:
  Consider the incidence of a time-harmonic electromagnetic plane wave onto a
biperiodic dielectric grating, where the surface is assumed to be a small and
smooth perturbation of a plane. The diffraction is modeled as a transmission
problem for Maxwell's equations in three dimensions. This paper concerns the
inverse diffraction problem which is to reconstruct the grating surface from
either the diffracted field or the transmitted field. A novel approach is
developed to solve the challenging nonlinear and ill-posed inverse problem. The
method requires only a single incident field and is realized via the fast
Fourier transform. Numerical results show that it is simple, fast, and stable
to reconstruct biperiodic dielectric grating surfaces with super-resolved
resolution.


title: Continued Fractions for Square Series Generating Functions

abstract:
  We consider new series expansions for variants of the so-termed ordinary
geometric square series generating functions originally defined in the recent
article titled "Square Series Generating Function Transformations" (arXiv:
1609.02803). Whereas the original square series transformations article adapts
known generating function transformations to construct integral representations
for these square series functions enumerating the square powers of $q^{n^2}$
for some fixed non-zero $q$ with $|q| < 1$, we study the expansions of these
special series through power series generated by Jacobi-type continued
fractions, or J-fractions. We prove new exact expansions of the $h^{th}$
convergents to these continued fraction series and show that the limiting case
of these convergent generating functions exists.
  We also prove new infinite $q$-series representations of special square
series expansions involving square-power terms of the series parameter $q$, the
$q$-Pochhammer symbol, and double sums over the $q$-binomial coefficients.
Applications of the new results we prove within the article include new
$q$-series representations for the ordinary generating functions of the special
sequences, $r_p(n)$, and $\sigma_1(n)$, as well as parallels to the examples of
the new integral representations for theta functions, series expansions of
infinite products and partition function generating functions, and related
unilateral special function series cited in the first square series
transformations article.


title:
Triclinic nematic colloidal crystals from competing elastic and
  electrostatic interactions

abstract:
  Self-assembly of nanoparticles can enable composites with pre-designed
properties but remains challenged by reproducing structural diversity of atomic
and molecular crystals. We combine anisotropic elastic and weakly screened
electrostatic interactions to guide both orientational and triclinic positional
self-ordering of inorganic nanocrystals in a nematic fluid host. The lattice
periodicity of these low-symmetry colloidal crystals is more than an order of
magnitude larger than the nanoparticle size. Orientations of nanocrystals, as
well as crystallographic axes of ensuing triclinic colloidal crystals, are
coupled to the uniform alignment direction of the nematic host, which can be
readily controlled on large scales. We probe colloidal pair and many-body
interactions and demonstrate how triclinic crystals with orientational ordering
of the semiconductor nanorods emerge from competing long-range elastic and
electrostatic forces.


title: Improved generator objectives for GANs

abstract:
  We present a framework to understand GAN training as alternating density
ratio estimation and approximate divergence minimization. This provides an
interpretation for the mismatched GAN generator and discriminator objectives
often used in practice, and explains the problem of poor sample diversity. We
also derive a family of generator objectives that target arbitrary
$f$-divergences without minimizing a lower bound, and use them to train
generative image models that target either improved sample quality or greater
sample diversity.


title:
Cooperative effect of doping and temperature on the polaronic band
  structure in strongly correlated electron systems with strong electron-phonon
  interaction

abstract:
  In this work we investigate doping and temperature dependences of electronic
structure of system with strong electronic correlations and strong
electron-phonon interaction modeling cuprates in the frameworks of the
three-band p-d-Holstein model by a polaronic version of the generalized tight
binding (GTB) method. Within this approach the electronic structure is formed
by polaronic quasiparticles constructed as excitations between initial and
final polaronic multielectron states. Doping and temperature effects are taken
into account by occupation numbers of local excited polaronic states and
variations in the magnitude of spin-spin correlation functions. Both effects
are manifested in the reconstruction of band structure, Fermi contours, density
of states and redistribution of the spectral weight over the Hubbard polaron
subbands. Doping leads to transformation of Fermi contour from small hole
pockets around k=(pi/2,pi/2) with inhomogeneous spectral weight distribution at
small hole concentration to large contour around k=(pi,pi) in the overdoped
compound as a result of two quantum phase transitions. In the system with
phonon subsystem and EPI doping results in the top of the valence band
splitting off and new polaron subbands appearance. Temperature increasing in
the system with doped holes and moderate EPI leads to formation of the flatband
around k=(pi,pi) and transfer of the spectral weight to the splitted off top of
the valence band.


title: Ergodic Theory and the Structure of Noncommutative Space-Time

abstract:
  We develop further our fibre bundle construct of non-commutative space-time
on a Minkowski base space. We assume space-time is non-commutative due to the
existence of additional non-commutative algebraic structure at each point x of
space-time, forming a quantum operator 'fibre algebra' A(x). This structure
then corresponds to the single fibre of a fibre bundle. A gauge group acts on
each fibre algebra locally, while a 'section' through this bundle is then a
quantum field of the form {A(x); x in M} with M the underlying space-time
manifold. In addition, we assume a local algebra O(D) corresponding to the
algebra of sections of such a principal fibre bundle with base space a finite
and bounded subset of space-time, D. The algebraic operations of addition and
multiplication are assumed defined fibrewise for this algebra of sections. We
characterise 'ergodic' extremal quantum states of the fibre algebra invariant
under the subgroup T of local translations of space-time of the Poincare group
P in terms of a non-commutative extension of entropy applied to the subgroup T.
We also characterise the existence of T- invariant states by generalizing to
the non-commutative case Kakutani's work on wandering projections. This leads
on to a classification of the structure of the local algebra O(D) by using a
'T-Twisted' equivalence relation, including a full analysis of the T-type III
case. In particular we show that O(D) is T-type III if and only if the crossed
product algebra O(D)xT is type III in the sense of Murray-von Neumann.


title: Inequalities for means of two mean variables

abstract:
  Motivated by the work of Anderson, Vamanamurthy and Vuorinen \cite{avv}, in
this paper authors study the log-convexity and log-concavity of Power mean,
Identric mean, weighted Power mean, Lehmer mean, Modified Alzer mean, and
establish the relation of these means with each other.


title:
Jonckheere-Terpstra test for nonclassical error versus log-sensitivity
  relationship of quantum spin network controllers

abstract:
  Selective information transfer in spin ring networks by energy landscape
shaping control has the property that the error 1-prob, where prob is the
transfer success probability, and the sensitivity of the error to spin coupling
uncertainties are statistically increasing across a family of controllers of
increasing error. The need for a statistical Hypothesis Testing of a concordant
trend is made necessary by the noisy behavior of the sensitivity versus the
error as a consequence of the optimization of the controllers in a challenging
error landscape. Here, we examine the concordant trend between the error and
another measure of performance - the logarithmic sensitivity - used in robust
control to formulate a well known fundamental limitation. Contrary to error
versus sensitivity, the error versus logarithmic sensitivity trend is less
obvious, because of the amplification of the noise due to the logarithmic
normalization. This results in the Kendall {\tau} test for rank correlation
between the error and the log sensitivity to be somewhat pessimistic with
marginal significance level. Here it is shown that the Jonckheere-Terpstra
test, because it tests the Alternative Hypothesis of an ordering of the medians
of some groups of log sensitivity data, alleviates this statistical problem.
This identifies cases of concordant trend between the error and the logarithmic
sensitivity, a highly anti-classical features that goes against the well know
sensitivity versus complementary sensitivity limitation.


title: Incorporating Quotation and Evaluation Into Church's Type Theory

abstract:
  ${\rm CTT}_{\rm qe}$ is a version of Church's type theory that includes
quotation and evaluation operators that are similar to quote and eval in the
Lisp programming language. With quotation and evaluation it is possible to
reason in ${\rm CTT}_{\rm qe}$ about the interplay of the syntax and semantics
of expressions and, as a result, to formalize syntax-based mathematical
algorithms. We present the syntax and semantics of ${\rm CTT}_{\rm qe}$ as well
as a proof system for ${\rm CTT}_{\rm qe}$. The proof system is shown to be
sound for all formulas and complete for formulas that do not contain
evaluations. We give several examples that illustrate the usefulness of having
quotation and evaluation in ${\rm CTT}_{\rm qe}$.


title: On the muon transfer from protium to neon at low collision energies

abstract:
  The direct muon transfer from protium to neon at low collision energies is
considered. The question is discussed how the energy dependence of the transfer
rate can be extracted from available experimental data. A model is suggested
which is based on two assumptions. First, the muon transfer occurs within an
interaction sphere out of which the entrance and transfer channels are not
coupled. Secondly, for the s- and p-waves at low collision energies, the
complex logarithmic derivatives of the radial wave functions of the entrance
channel on the interaction sphere are energy-independent. With only the s-wave
taken into account, two values of the logarithmic derivative were found, which
agree with the transfer rates measured at the temperatures of 20 and 300 K.
Within this temperature interval, the rates evaluated for these two values
differ only slightly. Noticeable differences arise at temperatures of a few
kelvins. The choice of the preferred value of the logarithmic derivative was
made by the comparison of the energy dependence of the S-matrix with results of
previous calculations. Thereby, the proposed procedure may be a way to correct
calculations at low collision energies.


title: The metallic winds in dwarf galaxies

abstract:
  We present results from models of galactic winds driven by energy injected
from nuclear (at the galactic center) and non-nuclear starbursts. The total
energy of the starburst is provided by very massive young stellar
clusters,which can push the galactic interstellar medium and produce an
important outflow. Such outflow can be a well, or partially mixed wind, or a
highly metallic wind. We have performed adiabatic 3D N-Body/Smooth Particle
Hydrodynamics simulations of galactic winds using the GADGET-2 code. The
numerical models cover a wide range of parameters, varying the galaxy
concentration index, gas fraction of the galactic disk, and radial distance of
the starburst. We show that an off-center starburst in dwarf galaxies is the
most effective mechanism to produce a significant loss of metals (material from
the starburst itself). At the same time a non-nuclear starburst produce a high
efficiency of metal loss, in spite of having a moderate to low mass loss rate.


title:
Faster Space-Efficient Algorithms for Subset Sum, k-Sum and Related
  Problems

abstract:
  We present space efficient Monte Carlo algorithms that solve Subset Sum and
Knapsack instances with $n$ items using $O^*(2^{0.86n})$ time and polynomial
space, where the $O^*(\cdot)$ notation suppresses factors polynomial in the
input size. Both algorithms assume random read-only access to random bits.
Modulo this mild assumption, this resolves a long-standing open problem in
exact algorithms for NP-hard problems. These results can be extended to solve
Binary Linear Programming on $n$ variables with few constraints in a similar
running time. We also show that for any constant $k\geq 2$, random instances of
$k$-Sum can be solved using $O(n^{k-0.5}polylog(n))$ time and $O(\log n)$
space, without the assumption of random access to random bits.
  Underlying these results is an algorithm that determines whether two given
lists of length $n$ with integers bounded by a polynomial in $n$ share a common
value. Assuming random read-only access to random bits, we show that this
problem can be solved using $O(\log n)$ space significantly faster than the
trivial $O(n^2)$ time algorithm if no value occurs too often in the same list.


title:
In the transmission of information, the great potential of model-based
  coding with the SP theory of intelligence

abstract:
  Model-based coding, described by John Pierce in 1961, has great potential to
reduce the volume of information that needs to be transmitted in moving big
data, without loss of information, from one place to another, or in lossless
communications via the internet. Compared with ordinary compression methods,
this potential advantage of model-based coding in the transmission of data
arises from the fact that both the transmitter ("Alice") and the receiver
("Bob") are equipped with a grammar for the kind of data that is to be
transmitted, which means that, to achieve lossless transmission of a body of
data from Alice and Bob, a relatively small amount of information needs to be
sent. Preliminary trials indicate that, with model-based coding, the volume of
information to be sent from Alice to Bob to achieve lossless transmission of a
given body of data may be less than $6\%$ of the volume of information that
needs to be sent when ordinary compression methods are used.
  Until recently, it has not been feasible to convert John Pierce's vision into
something that may be applied in practice. Now, with the development of the "SP
theory of intelligence" and its realisation in the "SP computer model", there
is clear potential to realise the three main functions that will be needed:
unsupervised learning of a grammar for the kind of data that is to be
transmitted using a relatively powerful computer that is independent of Alice
and Bob; the encoding by Alice of any one example of such data in terms of the
grammar; and, with the grammar, decoding of the encoding by Bob to retrieve the
given example. It appears now to be feasible, within reasonable timescales, to
bring these capabilities to a level where they may be applied to the
transmission of realistically large bodies of data.


title:
Six winters of photometry from Dome C, Antarctica: challenges,
  improvements, and results from the ASTEP experiment

abstract:
  ASTEP (Antarctica Search for Transiting ExoPlanets) is a pilot project that
aims at searching and characterizing transiting exoplanets from Dome C in
Antarctica and to qualify this site for photometry in the visible. Two
instruments were installed at Dome C and ran for six winters in total. The
analysis of the collected data is nearly complete. We present the operation of
the instruments, and the technical challenges, limitations, and possible
solutions in light of the data quality. The instruments performed continuous
observations during the winters. Human interventions are required mainly for
regular inspection and ice dust removal. A defrosting system is efficient at
preventing and removing ice on the mirrors. The PSF FWHM is 4.5 arcsec on
average which is 2.5 times larger than the specification, and is highly
variable; the causes are the poor ground-level seeing, the turbulent plumes
generated by the heating system, and to a lower extent the imperfect optical
alignment and focusing, and some astigmatism. We propose solutions for each of
these aspects that would largely increase the PSF stability. The astrometric
and guiding precisions are satisfactory and would deserve only minor
improvements. Major issues are encountered with the camera shutter which did
not close properly after two winters; we minimized this issue by heating the
shutter and by developing specific image calibration algorithms. Finally, we
summarize the site testing and science results obtained with ASTEP. Overall,
the ASTEP experiment will serve as a basis to design and operate future optical
and near-infrared telescopes in Antarctica.


title: Unitary Correlation Sets

abstract:
  The unitary correlation sets defined by the first author in conjunction with
tensor products of $\mathcal{U}_{nc}(n)$ are further studied. We show that
Connes' embedding problem is equivalent to deciding whether or not two smaller
versions of the unitary correlation sets are equal. Moreover, we obtain the
result that Connes' embedding problem is equivalent to deciding whether or not
two cross norms on $M_n \otimes M_n$ are equal for all $n \geq 2$.


title: Quantum propagation across cosmological singularities

abstract:
  The initial singularity is the most troubling feature of the standard
cosmology, which quantum effects are hoped to resolve. In this paper, we study
quantum cosmology with conformal (Weyl) invariant matter. We show it is natural
to extend the scale factor to negative values, allowing a large, collapsing
Universe to evolve across a quantum "bounce" into an expanding Universe like
ours. We compute the Feynman propagator for Friedmann-Robertson-Walker
backgrounds exactly, identifying curious pathologies in the case of curved
(open or closed) universes. We then include anisotropies, fixing the operator
ordering of the quantum Hamiltonian by imposing covariance under field
redefinitions and again finding exact solutions. We show how complex classical
solutions allow one to circumvent the singularity while maintaining the
validity of the semiclassical approximation. The simplest isotropic universes
sit on a critical boundary, beyond which there is qualitatively different
behavior, with potential for instability. Additional scalars improve the
theory's stability. Finally, we study the semiclassical propagation of
inhomogeneous perturbations about the flat, isotropic case, at linear and
nonlinear order, showing that, at least at this level, there is no particle
production across the bounce. These results form the basis for a promising new
approach to quantum cosmology and the resolution of the big bang singularity.


title:
Calculation of Momentum Distribution Function of a Non-thermal Fermionic
  Dark Matter

abstract:
  The most widely studied scenario in dark matter phenomenology is the thermal
WIMP scenario. Inspite of numerous efforts to detect WIMP, till now we have no
direct evidence for it. A possible explanation for this non-observation of dark
matter could be because of its very feeble interaction strength and hence,
failing to thermalise with the rest of the cosmic soup. In other words, the
dark matter might be of non-thermal origin where the relic density is obtained
by the so-called freeze-in mechanism. Furthermore, if this non-thermal dark
matter is itself produced substantially from the decay of another non-thermal
mother particle, then their distribution functions may differ in both size and
shape from the usual equilibrium distribution function. In this work, we have
studied such a non-thermal (fermionic) dark matter scenario in the light of a
new type of $U(1)_{\rm B-L}$ model. The $U(1)_{\rm B-L}$ model is interesting,
since, besides being anomaly free, it can give rise to neutrino mass by Type II
see-saw mechanism. Moreover, as we will show, it can accommodate a non-thermal
fermionic dark matter as well. Starting from the collision terms, we have
calculated the momentum distribution function for the dark matter by solving a
coupled system of Boltzmann equations. We then used it to calculate the final
relic abundance, as well as other relevant physical quantities. We have also
compared our result with that obtained from solving the usual Boltzmann (or
rate) equations directly in terms of comoving number density, $Y$. Our findings
suggest that the latter approximation is valid only in cases where the system
under study is close to equilibrium, and hence should be used with caution.


title: Change point detection in heteroscedastic time series

abstract:
  Many time series exhibit changes both in level and in variability. Generally,
it is more important to detect a change in the level, and changing or smoothly
evolving variability can confound existing tests. This paper develops a
framework for testing for shifts in the level of a series which accommodates
the possibility of changing variability. The resulting tests are robust both to
heteroskedasticity and serial dependence. They rely on a new functional central
limit theorem for dependent random variables whose variance can change or trend
in a substantial way. This new result is of independent interest as it can be
applied in many inferential contexts applicable to time series. Its application
to change point tests relies on a new approach which utilizes
Karhunen--Lo{\'e}ve expansions of the limit Gaussian processes. After
presenting the theory in the most commonly encountered setting of the detection
of a change point in the mean, we show how it can be extended to linear and
nonlinear regression. Finite sample performance is examined by means of a
simulation study and an application to yields on US treasury bonds.


title:
Safety Verification and Control for Collision Avoidance at Road
  Intersections

abstract:
  This paper presents the design of a supervisory algorithm that monitors
safety at road intersections and overrides drivers with a safe input when
necessary. The design of the supervisor consists of two parts: safety
verification and control design. Safety verification is the problem to
determine if vehicles will be able to cross the intersection without colliding
with current drivers' inputs. We translate this safety verification problem
into a jobshop scheduling problem, which minimizes the maximum lateness and
evaluates if the optimal cost is zero. The zero optimal cost corresponds to the
case in which all vehicles can cross each conflict area without collisions.
Computing the optimal cost requires solving a Mixed Integer Nonlinear
Programming (MINLP) problem due to the nonlinear second-order dynamics of the
vehicles. We therefore estimate this optimal cost by formulating two related
Mixed Integer Linear Programming (MILP) problems that assume simpler vehicle
dynamics. We prove that these two MILP problems yield lower and upper bounds of
the optimal cost. We also quantify the worst case approximation errors of these
MILP problems. We design the supervisor to override the vehicles with a safe
control input if the MILP problem that computes the upper bound yields a
positive optimal cost. We theoretically demonstrate that the supervisor keeps
the intersection safe and is non-blocking. Computer simulations further
validate that the algorithms can run in real time for problems of realistic
size.


title:
Characterizing a high spin magnetic impurity via Andreev reflection
  spectroscopy

abstract:
  The ground state properties of a high spin magnetic impurity and its
interaction with an electronic spin are probed via Andreev reflection. We see
that through the charge and spin conductance one can effectively estimate the
interaction strength, the ground state spin and magnetic moment of any high
spin magnetic impurity. We show how a high spin magnetic impurity at the
junction between a normal metal and superconductor can contribute to
superconducting spintronics applications. Particularly, while spin conductance
is absent below the gap for Ferromagnet-Insulator-Superconductor junctions we
show that in the case of a Normal metal-High spin magnetic impurity-Normal
Metal-Insulator-Superconductor (NMNIS) junction it is present. Further, it is
seen that pure spin conduction can exist without any accompanying charge
conduction in the NMNIS junction.


title: Locality and Unitarity from Singularities and Gauge Invariance

abstract:
  We conjecture that the leading two-derivative tree-level amplitudes for
gluons and gravitons can be derived from gauge invariance together with mild
assumptions on their singularity structure. Assuming locality (that the
singularities are associated with the poles of cubic graphs), we prove that
gauge-invariance in just (n-1) particles together with minimal power-counting
uniquely fixes the amplitude. Unitarity in the form of factorization then
follows from locality and gauge invariance. We also give evidence for a
stronger conjecture: assuming only that singularities occur when the sum of a
subset of external momenta go on-shell, we show in non-trivial examples that
gauge-invariance and power-counting demand a graph structure for singularities.
Thus both locality and unitarity emerge from singularities and gauge
invariance. Similar statements hold for theories of Goldstone bosons like the
non-linear sigma model and Dirac-Born-Infeld, by replacing the condition of
gauge invariance with an appropriate degree of vanishing in soft limits.


title: Octonionic two-qubit separability probability conjectures

abstract:
  We study, further, a conjectured formula for generalized two-qubit
Hilbert-Schmidt separability probabilities that has recently been proven by
Lovas and Andai (https://arxiv.org/pdf/1610.01410.pdf) for its real (two-rebit)
asserted value ($\frac{29}{64}$), and that has also been very strongly
supported numerically for its complex ($\frac{8}{33}$), and quaternionic
($\frac{26}{323}$) counterparts. Now, we seek to test the presumptive
octonionic value of $\frac{44482}{4091349} \approx 0.0108722$. We are somewhat
encouraged by certain numerical computations, indicating that this
(51-dimensional) instance of the conjecture might be fulfilled by setting a
certain determinantal-power parameter $a$, introduced by Forrester
(https://arxiv.org/pdf/1610.08081.pdf), to 0 (or possibly near to 0).
Hilbert-Schmidt measure being the case $k=0$ of random induced measure, for
$k=1$, the corresponding octonionic separability probability conjecture is
$\frac{7612846}{293213345} \approx 0.0259635$, while for $k=2$, it is
$\frac{4893392}{95041567} \approx 0.0514869, \ldots$. The relation between the
parameters $a$ and $k$ is explored.


title: On the volume of double twist link cone-manifolds

abstract:
  We consider the double twist link $J(2m+1, 2n+1)$ which is the two-bridge
link corresponding to the continued fraction $(2m+1)-1/(2n+1)$. It is known
that $J(2m+1, 2n+1)$ has reducible nonabelian $SL_2(\mathbb{C})$-character
variety if and only if $m=n$. In this paper we give a formula for the volume of
hyperbolic cone-manifolds of $J(2m+1,2m+1)$. We also give a formula for the
A-polynomial 2-tuple corresponding to the canonical component of the character
variety of $J(2m+1,2m+1)$.


title:
Strong convergence of tamed $\theta$-EM scheme for neutral SDDEs with
  one-sided Lipschitz drift

abstract:
  This paper is concerned with strong convergence of a tamed
$\theta$-Euler-Maruyama scheme for neutral stochastic differential delay
equations with superlinearly growing coefficients. We not only prove the strong
convergence of implicit schemes, but also reveal the convergence rate for these
equations driven by Brownian motion and pure jumps, respectively.


title: Discovering Conversational Dependencies between Messages in Dialogs

abstract:
  We investigate the task of inferring conversational dependencies between
messages in one-on-one online chat, which has become one of the most popular
forms of customer service. We propose a novel probabilistic classifier that
leverages conversational, lexical and semantic information. The approach is
evaluated empirically on a set of customer service chat logs from a Chinese
e-commerce website. It outperforms heuristic baselines.


title:
Interactive Prior Elicitation of Feature Similarities for Small Sample
  Size Prediction

abstract:
  Regression under the "small $n$, large $p$" conditions, of small sample size
$n$ and large number of features $p$ in the learning data set, is a recurring
setting in which learning from data is difficult. With prior knowledge about
relationships of the features, $p$ can effectively be reduced, but explicating
such prior knowledge is difficult for experts. In this paper we introduce a new
method for eliciting expert prior knowledge about the similarity of the roles
of features in the prediction task. The key idea is to use an interactive
multidimensional-scaling (MDS) type scatterplot display of the features to
elicit the similarity relationships, and then use the elicited relationships in
the prior distribution of prediction parameters. Specifically, for learning to
predict a target variable with Bayesian linear regression, the feature
relationships are used to construct a Gaussian prior with a full covariance
matrix for the regression coefficients. Evaluation of our method in experiments
with simulated and real users on text data confirm that prior elicitation of
feature similarities improves prediction accuracy. Furthermore, elicitation
with an interactive scatterplot display outperforms straightforward elicitation
where the users choose feature pairs from a feature list.


title: The Physical Systems Behind Optimization Algorithms

abstract:
  We use differential equations based approaches to provide some {\it
\textbf{physics}} insights into analyzing the dynamics of popular optimization
algorithms in machine learning. In particular, we study gradient descent,
proximal gradient descent, coordinate gradient descent, proximal coordinate
gradient, and Newton's methods as well as their Nesterov's accelerated variants
in a unified framework motivated by a natural connection of optimization
algorithms to physical systems. Our analysis is applicable to more general
algorithms and optimization problems {\it \textbf{beyond}} convexity and strong
convexity, e.g. Polyak-\L ojasiewicz and error bound conditions (possibly
nonconvex).


title:
Study of Dark-Matter Admixed Neutron Stars using the Equation of State
  from the Rotational Curves of Galaxies

abstract:
  In this work, we employ the dark matter equations of state (DMEOSs) obtained
from the rotational curves of galaxies as well as the fermionic DMEOS with m =
1.0 GeV to study the structure of darkmatter admixed neutron stars (DMANSs).
Applying the equation of state in the Skyrme framework for the neutron matter
(NM), we calculate the mass-radius relation for different DMANSs with various
DMEOSs and central pressure of dark matter (DM) to NM ratios. Our results show
that for some DMEOSs, the mass-radius relations are in agreement with new
observations, e.g. EXO 1745-248, 4U 1608-52, and 4U 1820-30, which are
inconsistent with the normal neutron stars. We conclude that both DMEOSs and
central pressure ratios of DM to NM affect the slope of the mass-radius
relation of DMANSs. This is because of the interaction between DM and NM, which
leads to gravitationally or self-bound DMANSs. We study the radius of the NM
sphere as well as the radius of the DM halo for different DMANSs. The results
confirm that, in some cases, a NM sphere with a small radius is surrounded by a
halo of DM with a larger radius. Our calculations verify that, due to the
different degrees of DM domination in DMANSs, with a value of the visible
radius of a star two possible DMANSs with different masses can be exist. The
gravitational redshift is also calculated for DMANSs with different DMEOSs and
central pressure ratios. The results explain that the existence of DM in a
DMANS leads to higher values of gravitational redshift of the star.


title:
Exploring the efficacy and limitations of shock-cooling models: new
  analysis of Type II supernovae observed by the Kepler mission

abstract:
  Modern transient surveys have begun discovering and following supernovae
(SNe) shortly after first light---providing systematic measurements of the rise
of Type II SNe. We explore how analytic models of early shock-cooling emission
from core-collapse SNe can constrain the progenitor's radius, explosion
velocity, and local host extinction. We simulate synthetic photometry in
several realistic observing scenarios and, assuming the models describe the
typical explosions well, find that ultraviolet observations can constrain the
progenitor's radius to a statistical uncertainty of $\pm10-15\%$, with a
systematic uncertainty of $\pm 20\%$. With these observations the local host
extinction ($A_V$) can be constrained to a factor of two and the shock velocity
to $\pm 5\%$ with a systematic uncertainty of $\pm 10\%$. We also re-analyze
the SN light curves presented in Garnavich et al. (2016) and find that KSN
2011a can be fit by a blue supergiant model with a progenitor radius of $R_s <
7.7 + 8.8 {\rm (stat)} + 1.9 {\rm (sys)}R_\odot$, while KSN 2011d can be fit
with a red supergiant model with a progenitor radius of $R_s = 111_{-21 {\rm
(stat)}}^{+89 {\rm (stat)}} \phantom{}_{-1{\rm (sys)}}^{+49 {\rm (sys)}}$. Our
results do not agree with those of Garnavich et al. (2016). Moreover, we
re-evaluate their claims and find that there is no statistically significant
evidence for a shock breakout flare in the light curve of KSN 2011d.


title: Quantum autoencoders for efficient compression of quantum data

abstract:
  Classical autoencoders are neural networks that can learn efficient low
dimensional representations of data in higher dimensional space. The task of an
autoencoder is, given an input $x$, is to map $x$ to a lower dimensional point
$y$ such that $x$ can likely be recovered from $y$. The structure of the
underlying autoencoder network can be chosen to represent the data on a smaller
dimension, effectively compressing the input. Inspired by this idea, we
introduce the model of a quantum autoencoder to perform similar tasks on
quantum data. The quantum autoencoder is trained to compress a particular
dataset of quantum states, where a classical compression algorithm cannot be
employed. The parameters of the quantum autoencoder are trained using classical
optimization algorithms. We show an example of a simple programmable circuit
that can be trained as an efficient autoencoder. We apply our model in the
context of quantum simulation to compress ground states of the Hubbard model
and molecular Hamiltonians.


title: Random versus maximum entropy models of neural population activity

abstract:
  The principle of maximum entropy provides a useful method for inferring
statistical mechanics models from observations in correlated systems, and is
widely used in a variety of fields where accurate data are available. While the
assumptions underlying maximum entropy are intuitive and appealing, its
adequacy for describing complex empirical data has been little studied in
comparison to alternative approaches. Here data from the collective spiking
activity of retinal neurons is reanalysed. The accuracy of the maximum entropy
distribution constrained by mean firing rates and pairwise correlations is
compared to a random ensemble of distributions constrained by the same
observables. In general, maximum entropy approximates the true distribution
better than the typical or mean distribution from that ensemble. This advantage
improves with population size, with groups as small as 8 being almost always
better described by maximum entropy. Failure of maximum entropy to outperform
random models is found to be associated with strong correlations in the
population.