  We introduce PLanetary Atmospheric Transmission for Observer Noobs (PLATON),
a Python package that calculates transmission spectra for exoplanets and
retrieves atmospheric characteristics based on observed spectra. PLATON is easy
to install and use, with common use cases taking no more than a few lines of
code. It is also fast, with the forward model taking much less than one second
and a typical retrieval finishing in minutes on an ordinary desktop. PLATON
supports the most common atmospheric parameters, such as temperature,
metallicity, C/O ratio, cloud-top pressure, and scattering slope. It also has
less commonly included features, such as a Mie scattering cloud model and
unocculted starspot corrections. The code is available online at
https://github.com/ideasrule/platon under the open source GPL-3.0 license.


  Encoders of AOM/AV1 codec consider an input video sequence as succession of
frames grouped in Golden-Frame (GF) groups. The coding structure of a GF group
is fixed with a given GF group size. In the current AOM/AV1 encoder, video
frames are coded using a hierarchical, multilayer coding structure within one
GF group. It has been observed that the use of multilayer coding structure may
result in worse coding performance if the GF group presents consistent
stillness across its frames. This paper proposes a new approach that adaptively
designs the Golden-Frame (GF) group coding structure through the use of
stillness detection. Our new approach hence develops an automatic stillness
detection scheme using three metrics extracted from each GF group. It then
differentiates those GF groups of stillness from other non- still GF groups and
uses different GF coding structures accordingly. Experimental result
demonstrates a consistent coding gain using the new approach.


  We present a two-scale approximation for the dynamics of a nonlinear
$\alpha^2$ dynamo. Solutions of the resulting nonlinear equations agree with
the numerical simulations of Brandenburg (2001), and show that $\alpha$ is
quenched by the buildup of magnetic helicity at the forcing scale $1/k_2$ as
the $\alpha$ effect transfers it from the large scale $1/k_1$. For times $t >
(k_1/k_2)R_{M,2}$ in eddy turnover units (where $R_{M,2}$ is the magnetic
Reynolds number of the forcing scale), $\alpha$ is resistively limited in the
form predicted for the steady-state case. However, for $t << R_{M,2}$, $\alpha$
takes on its kinematic value, independent of $R_{M,2}$, allowing the production
of large-scale magnetic energy equal to $k_1/k_2$ times equipartition. Thus the
dynamic theory of $\alpha$ predicts substantial "fast" growth of large-scale
field despite being "slow" at large times.


  There have been various attempts to identify groups of area-preserving
diffeomorphisms of 2-dimensional manifolds with limits of SU(N) as
$N\to\infty$. We discuss the particularly simple case where the manifold
concerned is the two-dimensional torus $T^2$ and argue that the limit, even in
the basis commonly used, is ill-behaved and that the large-N limit of SU(N) is
much larger than $SDiff(T^2)$.


  In this investigation we revisit the question of the linear stability
analysis of 2D steady Euler flows characterized by the presence of compact
regions with constant vorticity embedded in a potential flow. We give a
complete derivation of the linearized perturbation equation which, recognizing
that the underlying equilibrium problem is of the free-boundary type, is done
systematically using methods of the shape-differential calculus. Particular
attention is given to the proper linearization of the contour integrals
describing vortex induction. The thus obtained perturbation equation is
validated by analytically deducing from it the stability analyses of the
circular vortex, originally due to Kelvin (1880), and of the elliptic vortex,
originally due to Love (1893), as special cases. We also propose and validate a
spectrally-accurate numerical approach to the solution of the stability problem
for vortices of general shape in which all singular integrals are evaluated
analytically.


  Due to the subtle balance of intermolecular interactions that govern
structure-property relations, predicting the stability of crystal structures
formed from molecular building blocks is a highly non-trivial scientific
problem. A particularly active and fruitful approach involves classifying the
different combinations of interacting chemical moieties, as understanding the
relative energetics of different interactions enables the design of molecular
crystals and fine-tuning their stabilities. While this is usually performed
based on the empirical observation of the most commonly encountered motifs in
known crystal structures, we propose to apply a combination of supervised and
unsupervised machine-learning techniques to automate the construction of an
extensive library of molecular building blocks. We introduce a structural
descriptor tailored to the prediction of the binding (lattice) energy and apply
it to a curated dataset of organic crystals and exploit its atom-centered
nature to obtain a data-driven assessment of the contribution of different
chemical groups to the lattice energy of the crystal. We then interpret this
library using a low-dimensional representation of the structure-energy
landscape and discuss selected examples of the insights into crystal
engineering that can be extracted from this analysis, providing a complete
database to guide the design of molecular materials.


  This paper studies physical aging by computer simulations of a 2:1
Kob-Andersen binary Lennard-Jones mixture, a system that is less prone to
crystallization than the standard 4:1 composition. Starting from
thermal-equilibrium states, the time evolution of the following four quantities
is monitored following up and down jumps in temperature: the potential energy,
the virial, the average squared force, and the Laplacian of the potential
energy. Despite the fact that significantly larger temperature jumps are
studied here than in previous experiments, to a good approximation all four
quantities conform to the single-parameter-aging scenario derived and validated
for small jumps in experiments [Hecksher et al., J. Chem. Phys. 142, 241103
(2015)]. As a further confirmation of single-parameter aging with a common
material time for the different quantities monitored, their relaxing parts are
found to be almost identical for all temperature jumps.


  Coverage functions are an important subclass of submodular functions, finding
applications in machine learning, game theory, social networks, and facility
location. We study the complexity of partial function extension to coverage
functions. That is, given a partial function consisting of a family of subsets
of $[m]$ and a value at each point, does there exist a coverage function
defined on all subsets of $[m]$ that extends this partial function? Partial
function extension is previously studied for other function classes, including
boolean functions and convex functions, and is useful in many fields, such as
obtaining bounds on learning these function classes.
  We show that determining extendibility of a partial function to a coverage
function is NP-complete, establishing in the process that there is a
polynomial-sized certificate of extendibility. The hardness also gives us a
lower bound for learning coverage functions. We then study two natural notions
of approximate extension, to account for errors in the data set. The two
notions correspond roughly to multiplicative point-wise approximation and
additive $L_1$ approximation. We show upper and lower bounds for both notions
of approximation. In the second case we obtain nearly tight bounds.


  A new semi-discrete finite element scheme for the evolution of three
parametrized curves by curvature flow that are connected by a triple junction
is presented and analyzed. In this triple junction, conditions are imposed on
the angles at which the curves meet. One of the key problems in analyzing
motion of networks by curvature law is the choice of a tangential velocity that
allows for motion of the triple junction, does not lead to mesh degeneration,
and is amenable to an error analysis. Our approach consists in considering a
perturbation of a classical smooth formulation. The problem we propose admits a
natural variational formulation that can be discretized with finite elements.
The perturbation can be made arbitrarily small when a regularization parameter
shrinks to zero. Convergence of the new scheme including optimal error
estimates are proved. These results are supported by some numerical tests.
Finally, the influence of the small regularization parameter on the properties
of scheme and the accuracy of the results is numerically investigated.


  In this paper we characterize sharp time-data tradeoffs for optimization
problems used for solving linear inverse problems. We focus on the minimization
of a least-squares objective subject to a constraint defined as the sub-level
set of a penalty function. We present a unified convergence analysis of the
gradient projection algorithm applied to such problems. We sharply characterize
the convergence rate associated with a wide variety of random measurement
ensembles in terms of the number of measurements and structural complexity of
the signal with respect to the chosen penalty function. The results apply to
both convex and nonconvex constraints, demonstrating that a linear convergence
rate is attainable even though the least squares objective is not strongly
convex in these settings. When specialized to Gaussian measurements our results
show that such linear convergence occurs when the number of measurements is
merely 4 times the minimal number required to recover the desired signal at all
(a.k.a. the phase transition). We also achieve a slower but geometric rate of
convergence precisely above the phase transition point. Extensive numerical
results suggest that the derived rates exactly match the empirical performance.


  An algorithm to compute the set of prime implicates of a quantifier-free
clausal formula X in first order logic had been presented in earlier work. As
the knowledge base X is dynamic, new clauses are added to the old knowledge
base. In this paper an incremental algorithm is presented to compute the prime
implicates of X and a clause C from $\pi(X)\cup C$. The correctness of the
algorithm is also proved.


  Modulating energy states of metallic glasses (MGs) is significant in
understanding the nature of glasses and control their properties. In this
study, we show that rejuvenation in enthalpy can be achieved and preserved in
bulk MGs by using high pressure (HP) annealing, which is a controllable method
to continuously alter the energy states of MGs. Contrary to the decrease in
enthalpy by conventional annealing at ambient pressure, such rejuvenation can
occur and be enhanced by increasing both of annealing temperature and pressure.
By using double aberration corrected scanning transmission electron microscopy,
it is revealed that the rejuvenation, which is attributed to coupling effect of
high pressure and high temperature, originates from the microstructural change
that involves "negative flow units" with a higher atomic packing density
compared to that of the elastic matrix of MGs. The results demonstrate that HP
annealing is an effective way to rejuvenate MGs into higher energy states, and
it may assist in understanding the microstructural origin of the rejuvenation
in MGs.


  Deep learning has empowered analysis for single-cell sequencing data in many
ways and has generated deep understanding about a range of complex cellular
systems. As the booming single-cell sequencing technologies brings the surge of
high dimensional data that come from different sources and represent cellular
systems with different features, there is an equivalent rise and challenge of
integrating single-cell sequence across modalities. Here, we present a novel
adversarial approach to integrate single-cell chromatin accessibility and gene
expression data in a semi-supervised manner. We demonstrate that our method
substantially improves data integration from a simple adversarial domain
adaption approach, and it also outperforms two state-of-the-art (SOTA) methods.


  Traditional aerial vehicles have specific characteristics to perform specific
tasks but designing a versatile vehicle that can adapt depending on the task is
still a challenge. Based on modularity, we propose an aerial robotic system
that can increase its payload capacity and actuated degrees of freedom by
reconfiguring heterogeneous modules to adapt to different task specifications.
The system consists of cuboid modules propelled by quadrotors with tilted
rotors. We present two module designs with different actuation properties. By
assembling different types of modules, H-ModQuad can increase its actuated
degrees of freedom from 4 to 5 and 6 depending on its configuration. By
extending the concept of actuation ellipsoids, we find the body frame of a
vehicle with which the controller can maximize the maximum thrust. We use
polytopes to represent the actuation capability of the vehicles and examine
them against task requirements. We derive the modular vehicles' dynamics and
propose a general control strategy that applies for all possible numbers of
actuated degrees of freedom. The design is validated with simulations and
experiments using actual robots, showing that the modular vehicles provide
different actuation properties.


  Multidimensional Scaling (MDS) is a classic technique that seeks vectorial
representations for data points, given the pairwise distances between them.
However, in recent years, data are usually collected from diverse sources or
have multiple heterogeneous representations. How to do multidimensional scaling
on multiple input distance matrices is still unsolved to our best knowledge. In
this paper, we first define this new task formally. Then, we propose a new
algorithm called Multi-View Multidimensional Scaling (MVMDS) by considering
each input distance matrix as one view. Our algorithm is able to learn the
weights of views (i.e., distance matrices) automatically by exploring the
consensus information and complementary nature of views. Experimental results
on synthetic as well as real datasets demonstrate the effectiveness of MVMDS.
We hope that our work encourages a wider consideration in many domains where
MDS is needed.


  The ring of periodic distributions on ${\mathbb{R}}^{\tt d}$ with usual
addition and with convolution is considered. Via Fourier series expansions,
this ring is isomorphic to the ring ${\mathcal{S}}'({\mathbb{Z}}^{\tt d})$ of
all maps $f:{\mathbb{Z}}^{\tt d}\rightarrow \mathbb{C}$ of at most polynomial
growth (i.e., there exist a real $M>0$ and a nonnegative integer ${\tt m}$ such
that for all $\mathbf{n}=({\tt n}_1,\cdots, {\tt n}_{\tt d})\in
{\mathbb{Z}}^{\tt d}$, $ |f(\mathbf{n})|\leq M(1+|{\tt n}_1|+\cdots+|{\tt
n}_{\tt d}|)^{\tt m}$), with pointwise operations. It is shown that finitely
generated ideals in ${\mathcal{S}}'({\mathbb{Z}}^{\tt d})$ are principal, and
ideal membership is characterised analytically. Calling an ideal in
${\mathcal{S}}'({\mathbb{Z}}^{\tt d})$ fixed if there is a common index
$\mathbf{n} \in {\mathbb{Z}}^{\tt d}$ where each member vanishes, the fixed
maximal ideals are described, and it is shown that not all maximal ideals are
fixed. It is shown that finitely generated proper prime ideals in
${\mathcal{S}}'({\mathbb{Z}}^{\tt d})$ are fixed maximal ideals. The Krull
dimension of ${\mathcal{S}}'({\mathbb{Z}}^{\tt d})$ is proved to be infinite,
while the weak Krull dimension is shown to be equal to $1$.


  A central problem in computational statistics is to convert a procedure for
sampling combinatorial from an objects into a procedure for counting those
objects, and vice versa. Weconsider sampling problems coming from *Gibbs
distributions*, which are probability distributions of the form
$\mu^\Omega_\beta(\omega) \propto e^{\beta H(\omega)}$ for $\beta$ in an
interval $[\beta_\min, \beta_\max]$ and $H( \omega ) \in \{0 \} \cup [1, n]$.
The *partition function* is the normalization factor $Z(\beta)=\sum_{\omega
\in\Omega}e^{\beta H(\omega)}$.
  Two important parameters are the log partition ratio $q = \log
\tfrac{Z(\beta_\max)}{Z(\beta_\min)}$ and the vector of counts $c_x =
|H^{-1}(x)|$. Our first result is an algorithm to estimate the counts $c_x$
using roughly $\tilde O( \frac{q}{\epsilon^2})$ samples for general Gibbs
distributions and $\tilde O( \frac{n^2}{\epsilon^2} )$ samples for
integer-valued distributions (ignoring some second-order terms and parameters).
We show this is optimal up to logarithmic factors. We illustrate with improved
algorithms for counting connected subgraphs and perfect matchings in a graph.
  We develop a key subroutine for global estimation of the partition function.
Specifically, we produce a data structure to estimate $Z(\beta)$ for \emph{all}
values $\beta$, without further samples. Constructing the data structure
requires $O(\frac{q \log n}{\epsilon^2})$ samples for general Gibbs
distributions and $O(\frac{n^2 \log n}{\epsilon^2} + n \log q)$ samples for
integer-valued distributions. This improves over a prior algorithm of
Kolmogorov (2018) which computes the single point estimate $Z(\beta_\max)$
using $\tilde O(\frac{q}{\epsilon^2})$ samples. We also show that this
complexity is optimal as a function of $n$ and $q$ up to logarithmic terms.


  There are numerous advantages of using Electric Vehicles (EVs) as an
alternative method of transportation. However, an increase in EV usage in the
existing residential distribution grid poses problems such as overloading the
existing infrastructure. In this paper, we have modeled and simulated a
residential distribution grid in GridLAB-D (an open-source software tool used
to model, simulate, and analyze power distribution systems) to illustrate the
problems associated with a higher EV market penetration rates in the
residential domain. Power grid upgrades or control algorithms at the
transformer level are required to overcome issues such as transformer
overloading. We demonstrate the method of coordinating EV charging in a
residential distribution grid so as to overcome the overloading problem without
any upgrades in the distribution grid.


  Invariant tori play a fundamental role in the dynamics of symplectic and
volume-preserving maps. Codimension-one tori are particularly important as they
form barriers to transport. Such tori foliate the phase space of integrable,
volume-preserving maps with one action and $d$ angles. For the area-preserving
case, Greene's residue criterion is often used to predict the destruction of
tori from the properties of nearby periodic orbits. Even though KAM theory
applies to the three-dimensional case, the robustness of tori in such systems
is still poorly understood. We study a three-dimensional, reversible,
volume-preserving analogue of Chirikov's standard map with one action and two
angles. We investigate the preservation and destruction of tori under
perturbation by computing the "residue" of nearby periodic orbits. We find tori
with Diophantine rotation vectors in the "spiral mean" cubic algebraic field.
The residue is used to generate the critical function of the map and find a
candidate for the most robust torus.


  We define a new matrix-valued stochastic process with independent stationary
increments from the Laguerre Unitary Ensemble, which in a certain sense may be
considered a matrix generalisation of the gamma process. We show that
eigenvalues of this matrix-valued process forms a spatiotemporal determinantal
point process and give an explicit expression for the correlation kernel in
terms of Laguerre polynomials. Furthermore, we show that in an appropriate long
time scaling limit, this correlation kernel becomes identical to that of Dyson
Brownian Motion.


  We report the results of Monte Carlo simulations investigating the effect of
a spherical confinement within a simple model for a flexible homopolymer. We
use the parallel tempering method combined with multi-histogram reweighting
analysis and multicanonical simulations to investigate thermodynamical
observables over a broad range of temperatures, which enables us to describe
the behavior of the polymer and to locate the freezing and collapse
transitions. We find a strong effect of the spherical confinement on the
location of the collapse transition, whereas the freezing transition is hardly
effected.


  We review the asymmetries in top quark pair production at the Tevatron and
the LHC. We summarize the experimental measurements and the interpretations of
a possible excess in terms of new physics. We also review other top quark
properties-emphasizing effects related to the $t \bar t$ asymmetries-as well as
other collider signals.


  An approximate hadronic symmetry based on spin and flavor independence and
broken by spin and mass dependent terms is shown to follow from QCD. This
symmetry justifies the SU(6) classification scheme, but is more general in
allowing its supersymmetric extension based on a diquark-antiquark symmetry. It
will be shown that the same supersymmetry is also implied in the skyrmion type
effective Lagrangian which could be extracted from QCD. Predictions of the
Skyrme model is improved by using different realizations of the chiral group.


  We propose to measure the weak cosmic shear using the spatial derivatives of
the galaxy surface brightness field. The measurement should be carried out in
Fourier space, in which the point spread function (PSF) can be transformed to a
desired form with multiplications, and the spatial derivatives can be easily
measured. This method is mathematically well defined regardless of the galaxy
morphology and the form of the PSF, and involves simple procedures of image
processing. Furthermore, with high resolution galaxy images, this approach
allows one to probe the shape distortions of galaxy substructures, which can
potentially provide much more independent shear measurements than the
ellipticities of the whole galaxy. We demonstrate the efficiency of this method
using computer-generated mock galaxy images.


  We study the pure gauge model on a lattice manifold with trivial fundamental
homotopy group, homotopically equivalent to an $S_4$. Monopole loops may
fluctuate freely on that lattice without restrictions due to the boundary
conditions. For the original Wilson action on the hypertorus there is an
established two-state signal in energy distribution functions which disappears
for the new geometry. Our finite size scaling analysis suggests stringent upper
bounds on possible discontinuities in the plaquette action. However, no
consistent asymptotic finite size scaling behaviour is observed.


  Topological insulators (TIs) are bulk insulators that possess robust helical
conducting states along their interfaces with conventional insulators. A
tremendous research effort has recently been devoted to TI-based
heterostructures, in which conventional proximity effects give rise to a series
of exotic physical phenomena. This paper reviews our recent works on the
potential existence of topological proximity effects at the interface between a
topological insulator and a normal insulator or other topologically trivial
systems. Using first-principles approaches, we have established the tunability
of the vertical location of the topological helical state via intriguing
dual-proximity effects. To further elucidate the control parameters of this
effect, we have used the graphene-based heterostructures as prototypical
systems to reveal a more complete phase diagram. On the application side of the
topological helical states, we have presented a catalysis example, where the
topological helical state plays an essential role in facilitating surface
reactions by serving as an effective electron bath. These discoveries lay the
foundation for accurate manipulation of the real space properties of the
topological helical state in TI-based heterostructures and pave the way for
realization of the salient functionality of topological insulators in future
device applications.


  The cosmological {7Li problem consists in explaining why the primordial Li
abundance, as predicted by the standard Big Bang nucleosynthesis theory with
constraints from WMAP and Planck, is a factor of 3 larger than the Li abundance
measured in the stars of the Spite plateau defined by old, warm dwarf stars of
the Milky Way halo. Several explanations have been proposed to explain this
difference, including various Li depletion processes as well as non standard
Big Bang nucleosynthesis, but the main question remains unanswered. In this
paper, we present detailed chemical evolution models for dwarf spheroidal and
ultra faint galaxies, compute the galactic evolution of 7Li abundance in these
objects and compare it with observations of similar objects. In our models, Li
is mainly produced by novae and cosmic rays and to a minor extent by low and
intermediate mass stars. We adopt the yield combination which best fits the Li
abundances in the Milky Way stars. It is evident that the observations of dwarf
objects define a Spite plateau, identical to that observed in the Milky Way,
thus suggesting that the Spite plateau could be a universal feature and its
meaning should be discussed. The predictions of our models for dwarf galaxies,
are obtained by assuming as Li primordial abundance either the one detected in
the atmospheres of the oldest halo stars (Spite plateau; A(Li)=2.2 dex), or the
one from cosmological observations (WMAP; A(Li)=2.66 dex). Finally, we discuss
the implications of the universality of the Spite plateau results.


  The evolution of the nuclear shapes along the triaxial landscape is studied
in the Pt isotopic chain using the selfconsistent Hartree-Fock-Bogoliubov
approximation based on the Gogny interaction. In addition to the
parametrization D1S, the new incarnations D1N and D1M of this force are also
included in our analysis to asses to which extent the predictions are
independent of details of the effective interaction. The considered range of
neutron numbers 88<N<26 includes prolate, triaxial, oblate and spherical ground
state shapes and serves for a detailed comparison of the predictions obtained
with the new sets D1N and D1M against the ones provided by the standard
parametrization Gogny-D1S in a region of the nuclear landscape for which
experimental and theoretical fingerprints of shape transitions have been found.
Structural evolution along the Pt chain is discussed in terms of the
deformation dependence of single particle energies.


  The physical origin of the X-ray emission in powerful quasar jets has been a
long-standing mystery. Though these jets start out on the sub-pc scale as
highly relativistic flows, we do not have any direct measurement of their
speeds on the kpc scale, where the vast distances from the core necessitate in
situ particle acceleration. If the jets remain highly relativistic on kpc
scales, then the X-rays could be due to inverse-Compton upscattering of CMB
photons. However, the IC/CMB explanation predicts a high level of gamma-ray
emission, which should be detectible by the Fermi/LAT. We have searched for and
ruled out this emission at a high level of significance for the well-known
sources 3C 273 and PKS 0637-752, suggesting the X-rays are synchrotron, though
of unknown origin. These recent results with Fermi also suggest that the
kpc-scale jets in powerful quasars are significantly slower than have been
presumed under the IC/CMB model. I will discuss the surprising implications of
these findings for the energetics and radiative output of powerful quasars as
well as their impact on their environment.


  We obtained exact-order estimates for the entropy numbers of the
Nikol'skii-Besov classes $B^{\boldsymbol{r}}_{p,\theta}$ of periodic functions
of many variables in the metric of the space of quasi-continuous functions.


  A graph is near-bipartite if its vertex set can be partitioned into an
independent set and a set which induces a forest. In this paper, planar graphs
without cycles of length from 4 to 7 are shown to be near-bipartite.


  We study the asymptotic volume ratio of non-steady gradient Ricci solitons.
Moreover, a local estimate of the volume ratio is obtained for expanding
solitons which satisfy $\lim_{dist(O,x)\rightarrow\infty} |Sect|\cdot
dist(O,x)^2=0$. Therefore, for such a soliton, we can show that it must have
$\mathbb{R}^n$ as one of its tangent cone at infinity. (Here we assume that the
soliton is simply connected at infinity, has only one end and $n\geq 3$.)


  Let $G$ be a finite group and $\chi\in \irr(G)$. The codegree of $\chi$ is
defined as
  $\cod(\chi)=\frac{|G:\ker(\chi)|}{\chi(1)}$ and $\cod(G)=\{\cod(\chi) \ |\
\chi\in \irr(G)\}$ is called the set of codegrees of $G$. In this paper, we
show that the set of codegrees of $\PSL(3,q)$ and $\PSU(3,q)$ determines the
group up to isomorphism.


  We present tentative evidence for the existence of a dissolved star cluster
at [Fe/H]=-2.7 in the Sextans dwarf spheroidal galaxy. We use the technique of
chemical tagging to identify stars that are highly clustered in a
multi-dimensional chemical abundance space (C-space). In a sample of six stars,
three, possibly four stars are identified as potential cluster stars. The
initial stellar mass of the parent cluster is estimated from two independent
observations to M*,init=1.9^{+1.5}_{-0.9} (1.6^{+1.2}_{-0.8}) x 10^5 M_sol,
assuming a Salpeter (Kroupa) initial mass function (IMF). If corroborated by
follow-up spectroscopy, this star cluster is the most metal-poor system
identified to date. Chemical signatures of remnant clusters in dwarf galaxies
like Sextans provide us with a very powerful probe to the high-redshift
Universe. From available observational data, we argue that the average star
cluster mass in the majority of the newly discovered ultra-faint dwarf galaxies
was notably lower than it is in the Galaxy today and possibly lower than in the
more luminous, classical dwarf spheroidal galaxies. Furthermore, the mean
cumulative metallicity function of the dwarf spheroidals falls below that of
the ultra-faints, which increases with increasing metallicity as predicted from
our stochastic chemical evolution model. These two findings, together with a
possible difference in the <[Mg/Fe]> ratio suggest that the ultra-faint dwarf
galaxy population, or a significant fraction thereof, and the dwarf spheroidal
population, were formed in different environments and would thus be distinct in
origin.


  We study both strict and mild solutions to parabolic evolution equations of
the form $dX+AXdt=F(t)dt+G(t)dW(t)$ in Banach spaces. First, we explore the
deterministic case. The maximal regularity of solutions has been shown. Second,
we investigate the stochastic case. We prove existence of strict solutions and
show their space-time regularity. Finally, we apply our abstract results to a
stochastic heat equation.


  We introduce a (conjecturally complete) topological invariant of isotopy
classes of Morse polynomials ${\mathbb R}^3 \to {\mathbb R}^1$ of degree 3 with
non-degenerate principal homogeneous part, calculate all 36 possible values of
this invariant, and realize them all (except one) by real polynomials, at which
these values are taken.
  We also demonstrate many examples of non-typical adjacencies of
multisingularity classes (namely, the pairs of simple function singularities
with the sum of the Milnor numbers equal to 8) to singularities of class $P_8$,
which break the equisingularity of bifurcation sets of functions along the
$\mu=\mbox{const} $ stratum of type $P_8$. At the same time, we prove the
non-existence of many other such adjacencies.
  These results are obtained with the help of a combinatorial computer program
formalizing Morse surgeries, local monodromy and the Picard-Lefschetz theory,
which I promote and recommend to the readers.


  In this paper, we integrate a simple non-parallel voice conversion (VC)
system with a WaveNet (WN) vocoder and a proposed collapsed speech suppression
technique. The effectiveness of WN as a vocoder for generating high-fidelity
speech waveforms on the basis of acoustic features has been confirmed in recent
works. However, when combining the WN vocoder with a VC system, the distorted
acoustic features, acoustic and temporal mismatches, and exposure bias usually
lead to significant speech quality degradation, making WN generate some very
noisy speech segments called collapsed speech. To tackle the problem, we take
conventional-vocoder-generated speech as the reference speech to derive a
linear predictive coding distribution constraint (LPCDC) to avoid the collapsed
speech problem. Furthermore, to mitigate the negative effects introduced by the
LPCDC, we propose a collapsed speech segment detector (CSSD) to ensure that the
LPCDC is only applied to the problematic segments to limit the loss of quality
to short periods. Objective and subjective evaluations are conducted, and the
experimental results confirm the effectiveness of the proposed method, which
further improves the speech quality of our previous non-parallel VC system
submitted to Voice Conversion Challenge 2018.


  We use 25 simulated galaxies from the NIHAO project to define and
characterize a variety of kinematic stellar structures: thin and thick discs,
large scale single discs, classical and pseudo bulges, spheroids, inner discs,
and stellar haloes. These structures have masses, spins, shapes and rotational
support in good agreement with theoretical expectations and observational data.
Above a dark matter halo mass of $2.5\times10^{\rm~11}M_{\rm\odot}$, all
galaxies have a classical bulge and 70\% have a thin and thick disc. The
kinematic (thin) discs follow a power-law relation between angular momentum and
stellar mass $J_{\rm *}=3.4M_{\rm *}^{\rm1.26\pm0.06}$, in very good agreement
with the prediction based on the empirical stellar-to-halo mass relation in the
same mass range, and show a strong correlation between maximum `observed'
rotation velocity and dark matter halo circular velocity $v_{\rm c}=6.4v_{\rm
max}^{0.64\pm0.04}$. Tracing back in time these structures' progenitors, we
find all to lose a fraction $1-f_j$ of their maximum angular momentum. Thin
discs are significantly better at retaining their high-redshift spins
($f_j\sim0.70$) than thick ones ($f_j\sim0.40$). Stellar haloes have their
progenitor baryons assembled the latest ($z_{\rm~1/2}\sim1.1$) and over the
longest timescales ($\tau\sim6.2$~Gyr), and have the smallest fraction of stars
born in-situ ($f_{\rm in-situ}=0.35\pm0.14$). All other structures have
$1.5\lesssim z_{\rm1/2}\lesssim3$, $\tau=4\pm2$~Gyr and $f_{\rm
in-situ}\gtrsim0.9$.


  A different application of the familiar integral representation for the
modifed Bessel function drives to a new Kontorovich-Lebedev-like integral
transformation of a general complex index. Mapping and operational properties,
a convolution operator and inversion formula are established. Solvability
conditions and explicit solutions of the corresponding class of convolution
integral equations are exhibited.


  A new section on projections of coherent sheaves from a projective space to a
lower-dimensional projective space has been added.
  Also some of the notation has been altered to bring it into line with the
joint paper with Eisenbud and Schreyer.


  In this paper we analyze the notion of "stopping time complexity", informally
defined as the amount of information needed to specify when to stop while
reading an infinite sequence. This notion was introduced by Vovk and Pavlovic
(2016). It turns out that plain stopping time complexity of a binary string $x$
could be equivalently defined as (a) the minimal plain complexity of a Turing
machine that stops after reading $x$ on a one-directional input tape; (b) the
minimal plain complexity of an algorithm that enumerates a prefix-free set
containing $x$; (c)~the conditional complexity $C(x|x*)$ where $x$ in the
condition is understood as a prefix of an infinite binary sequence while the
first $x$ is understood as a terminated binary string; (d) as a minimal upper
semicomputable function $K$ such that each binary sequence has at most $2^n$
prefixes $z$ such that $K(z)<n$; (e) as $\max C^X(x)$ where $C^X(z)$ is plain
Kolmogorov complexity of $z$ relative to oracle $X$ and the maximum is taken
over all extensions $X$ of $x$.
  We also show that some of these equivalent definitions become non-equivalent
in the more general setting where the condition $y$ and the object $x$ may
differ. We also answer an open question from Chernov, Hutter and~Schmidhuber.


  Extracting predictive models from nonlinear systems is a central task in
scientific machine learning. One key problem is the reconciliation between
modern data-driven approaches and first principles. Despite rapid advances in
machine learning techniques, embedding domain knowledge into data-driven models
remains a challenge. In this work, we present a universal learning framework
for extracting predictive models from nonlinear systems based on observations.
Our framework can readily incorporate first principle knowledge because it
naturally models nonlinear systems as continuous-time systems. This both
improves the extracted models' extrapolation power and reduces the amount of
data needed for training. In addition, our framework has the advantages of
robustness to observational noise and applicability to irregularly sampled
data. We demonstrate the effectiveness of our scheme by learning predictive
models for a wide variety of systems including a stiff Van der Pol oscillator,
the Lorenz system, and the Kuramoto-Sivashinsky equation. For the Lorenz
system, different types of domain knowledge are incorporated to demonstrate the
strength of knowledge embedding in data-driven system identification.


  We present DeepTract, a deep-learning framework for estimating white matter
fibers orientation and streamline tractography. We adopt a data-driven approach
for fiber reconstruction from diffusion weighted images (DWI), which does not
assume a specific diffusion model. We use a recurrent neural network for
mapping sequences of DWI values into probabilistic fiber orientation
distributions. Based on these estimations, our model facilitates both
deterministic and probabilistic streamline tractography. We quantitatively
evaluate our method using the Tractometer tool, demonstrating competitive
performance with state-of-the art classical and machine learning based
tractography algorithms. We further present qualitative results of
bundle-specific probabilistic tractography obtained using our method. The code
is publicly available at: https://github.com/itaybenou/DeepTract.git.


  Sicily has played an important role in the development of the new research
area named "Econophysics". In fact some key ideas supporting this new hybrid
discipline were originally formulated in a pioneering work of the Sicilian born
physicist Ettore Majorana. The article he wrote was entitled "The value of
statistical laws in physics and social sciences". I will discuss its origin and
history that has been recently discovered in the study of Stefano Roncoroni.
This recent study documents the true reasons and motivations that triggered the
pioneering work of Majorana. It also shows that the description of this work
provided by Edoardo Amaldi was shallow and misleading. In the second part of
the talk I will recollect the first years of development of econophysics and in
particular the role of the "International Workshop on Econophysics and
Statistical Finance" held in Palermo on 28-30 September 1998 and the setting in
1999 of the "Observatory of Complex Systems" the research group on Econophysics
of Palermo University and Istituto Nazionale di Fisica della Materia.


  We introduce a general formalism with minimal requirements under which we are
able to prove the pro-modular Fontaine-Mazur conjecture. We verify it in the
ordinary case using the recent construction of Breuil and Herzig.


  Single molecule rotational correlation functions are analyzed for several
reorientation geometries. Even for the simplest model of isotropic rotational
diffusion our findings predict non-exponential correlation functions to be
observed by polarization sensitive single molecule fluorescence microscopy.
This may have a deep impact on interpreting the results of molecular
reorientation measurements in heterogeneous environments.


  A reference frame F is described by the element g of the Poincare' group P
which connects F with a given fixed frame F_0. If F is a quantum frame, defined
by a physical object following the laws of quantum physics, the parameters of g
have to be considered as quantum observables. However, these observables are
not compatible and some of them, namely the coordinates of the origin of F,
cannot be represented by self-adjoint operators. Both these difficulties can be
overcome by considering a positive-operator-valued measure (POVM) on P,
covariant with respect to the left translations of the group, namely a
covariance system. We develop a construction procedure for this kind of
mathematical structure. The formalism is also used to discuss the quantum
observables measured with respect to a quantum reference frame.


  There is a constant c contained in the famous radial basis function shifted
surface spline. It's called shape parameter. RBF people only know that this
constant is very influential, while its optimal choice is unknown. This paper
presents criteria of its optimal choice.


  We present results of the first multicolour photometric study of 4U1957+115,
one of the optically less studied low mass X-ray binaries (LMXB). Our
quasi-simultaneous UBVRI observations reveal that the light curve pulse shape
over the 9.33 hr period discovered by Thorstensen (1987) has changed
substantially since his earlier V band studies. The light curve now shows clear
asymmetry and an amplitude more than double of that seen by Thorstensen (1987).
The light curve also shows colour dependence that seems to rule out the X-ray
heating model as an origin for photometric variability. We believe that the
changes observed in the light curve shape are indicative of evolving accretion
disk structure. We discuss implications of this on the origin of optical
emission in 4U1957+115 and disk accreting binaries in general.


  The library serves as a vehicle for education, research, conservation,
information, and recreation to improve the nation's intelligence and
empowerment [1]. The function of the library as a place of education, research,
and information provides an opportunity to use the information system of
Senayan Library Management System (SLiMS) in the library in order to improve
the service to the user, increase the reading interest, and expand the insight
and knowledge to educate the nation. The use of ISO 9126 standard is able to
know the quality of SLiMS information system which is said to be free of charge
of usage and license (because it belongs to Open Source Software category [2])
to assist library management in Indonesia. The implementation of the SLiMS
information system audit in several university libraries refers to the ISO 9126
standard by using the Functionality, Reliability, Usability, Efficiency,
Maintainability and Portability aspects through distributing questionnaires to
university librarians in charge. With the help of the use of Google Forms it
turns out that only ten universities librarians in charge who are willing to
fill out the questionnaires are IPMI IBS, Bakrie University, Perbanas Institute
Jakarta, STMIK & Bina Insani Academy, Prasetya Mulya University, Agung Podomoro
University, Indonesian Higher Law School, Matana University, STIKS Tarakanita
Jakarta, and STAI-PIQ West Sumatra. From the results of data processing it is
known that SLiMS included in the category VERY GOOD for use in the management
of libraries in college. This means that the ten universities librarians in
charge admitted and have proven that SLiMS is very helpful in library
management.


  The detection of the flavour content of jets produced from R-parity violating
neutralino decays is investigated in the case where one baryon-number violating
coupling dominates. Simulations are performed of the ATLAS experiment at the
LHC for all couplings, other than lambda"_tjk since neutralino decays through
these couplings are very suppressed. Secondary vertex distributions and muons
produced by heavy-quark (b- and c-) jets allow discrimination between LSP decay
modes. The dominant coupling can be identified at better than 3.5 sigma in
almost all cases, with the only remaining ambiguity caused by the inability to
distinguish strange from down quarks.


  We investigate when a commutative ring spectrum $R$ satisfies a homotopical
version of local Gorenstein duality, extending the notion previously studied by
Greenlees. In order to do this, we prove an ascent theorem for local Gorenstein
duality along morphisms of $k$-algebras. Our main examples are of the form $R =
C^*(X;k)$, the ring spectrum of cochains on a space $X$ for a field $k$. In
particular, we establish local Gorenstein duality in characteristic $p$ for
$p$-compact groups and $p$-local finite groups as well as for $k = \Q$ and $X$
a simply connected space which is Gorenstein in the sense of Dwyer, Greenlees,
and Iyengar.


  We prove the unconditional security of coherent-state-based differential
phase shift quantum key distribution protocol (DPSQKD) with block-wise phase
randomization. Our proof is based on the conversion of DPSQKD to an equivalent
entanglement-distillation protocol where the estimated phase error rate
determines the amount of the privacy amplification. The generated final key has
a contribution from events where the sender emits two or more photons,
indicating the robustness of DPSQKD against photon-number-splitting attacks.


  We revisit computationally relaxed locally decodable codes (crLDCs) (Blocki
et al., Trans. Inf. Theory '21) and give two new constructions. Our first
construction is a Hamming crLDC that is conceptually simpler than prior
constructions, leveraging digital signature schemes and an appropriately chosen
Hamming code. Our second construction is an extension of our Hamming crLDC to
handle insertion-deletion (InsDel) errors, yielding an InsDel crLDC. This
extension crucially relies on the noisy binary search techniques of Block et
al. (FSTTCS '20) to handle InsDel errors. Both crLDC constructions have binary
codeword alphabets, are resilient to a constant fraction of Hamming and InsDel
errors, respectively, and under suitable parameter choices have
poly-logarithmic locality and encoding length linear in the message length and
polynomial in the security parameter. These parameters compare favorably to
prior constructions in the poly-logarithmic locality regime.


  We study the practical effectiveness of privacy amplification for classical
key-distribution schemes. We find that in contrast to quantum key distribution
schemes, the high fidelity of the raw key generated in classical systems allow
the users to always sift a secure shorter key if they have an upper bound on
the eavesdropper probability to correctly guess the exchanged key-bits. The
number of privacy amplification iterations needed to achieve information leak
of 10^-8 in existing classical communicators is 2 or 3 resulting in a
corresponding slowdown 4 to 8. We analyze the inherent tradeoff between the
number of iterations and the security of the raw key. This property which is
unique to classical key distribution systems render them highly useful for
practical, especially for noisy channels where sufficiently low quantum bit
error ratios are difficult to achieve.


  Quantum teleportation is an essential application of quantum entanglement.
The examination of teleportation fidelity in two-party standard teleportation
schemes reveals a critical threshold distinguishing separable and entangled
states. For separable states, their teleportation fidelities cannot exceed the
threshold, emphasizing the significance of entanglement. We extend this
analysis to multi-party scenarios known as controlled teleportation. Our study
provides thresholds that $N$-qudit $k$-separable states cannot exceed in a
controlled teleportation scheme, where $N \ge 3$ and $2 \le k \le N$. This not
only establishes a standard for utilizing a given quantum state as a resource
in controlled teleportation but also enhances our understanding of the
influence of the entanglement structure on controlled teleportation
performance. In addition, we show that genuine multipartite entanglement is not
a prerequisite for achieving a high controlled teleportation capability.


  Recently, Daligault, Rao and Thomass\'e asked in [3] if every hereditary
class which is well-quasi-ordered by the induced subgraph relation is of
bounded clique-width. There are two reasons why this questions is interesting.
First, it connects two seemingly unrelated notions. Second, if the question is
answered affirmatively, this will have a strong algorithmic consequence. In
particular, this will mean (through the use of Courcelle theorem [2]), that any
problem definable in Monadic Second Order Logic can be solved in a polynomial
time on any class well-quasi-ordered by the induced subgraph relation. In the
present paper, we answer this question affirmatively for graphs without large
bicliques. Thus the above algorithmic consequence is true, for example, for
classes of graphs of bounded degree.


  We present a study on the magnetization, anomalous Hall effect (AHE) and
novel longitudinal resistivity in layered antiferromagnet Co$_{0.29}$TaS$_{2}$.
Of particular interests in Co$_{0.29}$TaS$_{2}$ are abundant magnetic
transitions, which show that the magnetic structures are tuned by temperature
or magnetic field. With decreasing temperature, Co$_{0.29}$TaS$_{2}$ undergoes
two transitions at T$_{t1}\sim$ 38.3 K and T$_{t2}\sim$ 24.3 K. Once the
magnetic field is applied, another transition T$_{t3}\sim$ 34.3 K appears
between 0.3 T and 5 T. At 2 K, an obvious ferromagnetic hysteresis loop within
H$_{t1}\sim\pm$ 6.9 T is observed, which decreases with increasing temperature
and eventually disappears at T$_{t2}$. Besides, Co$_{0.29}$TaS$_{2}$ displays
step-like behavior as another magnetic transition around H$_{t2}\sim\pm$ 4 T,
which exists until $\sim$ T$_{t1}$. These characteristic temperatures and
magnetic fields mark complex magnetic phase transitions in
Co$_{0.29}$TaS$_{2}$, which are also evidenced in transport results. Large AHE
dominates in the Hall resistivity with the conspicuous value of
R$_{s}$/R$_{0}\sim 10^{5}$, considering that the tiny net magnetization
(0.0094$\mu_{B}$/Co) alone would not lead to this value, thus the contribution
of Berry curvature is necessary. The longitudinal resistivity illustrates a
prominent irreversible behavior within H$_{t1}$. The abrupt change at H$_{t2}$
below T$_{t1}$, corresponding to the step-like magnetic transitions, is also
observed. Synergy between the magnetism and topological properties, both
playing a crucial role, may be the key factor of large AHE in antiferromagnet,
which also offers a new perspective in magnetic topological materials with the
platform of Co$_{0.29}$TaS$_{2}$.


  The 10 MeV accelerator-driven subcritical system (ADS) Injector-I test stand
at Institute of High Energy Physics (IHEP) is a testing facility dedicated to
demonstrate one of the two injector design schemes [Injector Scheme-I, which
works at 325 MHz], for the ADS project in China. The Injector adopted a four
vane copper structure RFQ with output energy of 3.2 MeV and a superconducting
(SC) section accommodating fourteen \b{eta}g=0.12 single spoke cavities,
fourteen SC solenoids and fourteen cold BPMs. The ion source was installed
since April of 2014, periods of commissioning are regularly scheduled between
installation phases of the rest of the injector. Continuous wave (CW) beam was
shooting through the injector and 10 MeV CW proton beam with average beam
current around 2 mA was obtained recently. This contribution describe the
results achieved so far and the difficulties encountered in CW commissioning.


  Chemical-chemical interaction (CCI) plays a key role in predicting candidate
drugs, toxicity, therapeutic effects, and biological functions. In various
types of chemical analyses, computational approaches are often required due to
the amount of data that needs to be handled. The recent remarkable growth and
outstanding performance of deep learning have attracted considerable research
attention. However,even in state-of-the-art drug analysis methods, deep
learning continues to be used only as a classifier, although deep learning is
capable of not only simple classification but also automated feature
extraction. In this paper, we propose the first end-to-end learning method for
CCI, named DeepCCI. Hidden features are derived from a simplified molecular
input line entry system (SMILES), which is a string notation representing the
chemical structure, instead of learning from crafted features. To discover
hidden representations for the SMILES strings, we use convolutional neural
networks (CNNs). To guarantee the commutative property for homogeneous
interaction, we apply model sharing and hidden representation merging
techniques. The performance of DeepCCI was compared with a plain deep
classifier and conventional machine learning methods. The proposed DeepCCI
showed the best performance in all seven evaluation metrics used. In addition,
the commutative property was experimentally validated. The automatically
extracted features through end-to-end SMILES learning alleviates the
significant efforts required for manual feature engineering. It is expected to
improve prediction performance, in drug analyses.


  We present a proof of a multidimensional version of Peres-Schlag's theorem on
Diophantine approximations with lacunary sequences.


  A full-dimensional molecular model of water, HBB2-pol, derived entirely from
first principles, is introduced and employed in computer simulations ranging
from the dimer to the liquid. HBB2-pol provides excellent agreement with the
measured second and third virial coefficients and, by construction, reproduces
the dimer vibration-rotation tunneling spectrum. The model also predicts the
relative energy differences between isomers of small water clusters within the
accuracy of highly correlated electronic structure methods. Importantly, when
combined with simulation methods that explicitly include zero-point energy and
quantum thermal motion, HBB2-pol accurately describes both structural and
dynamical properties of the liquid phase. The predictive power of the HBB2-pol
quantum simulations opens the door to the long-sought molecular-level
understanding of water under different conditions and in different
environments.


  Several recent papers have focused their attention in proving the correct
analogue to the Lieb-Thirring inequalities for non self-adjoint operators and
in finding bounds on the distribution of their eigenvalues in the complex
plane. This paper provides some improvement in the state of the art in this
topic. Precisely, we address the question of finding quantitative bounds on the
discrete spectrum of the perturbed Lam\'e operator of elasticity $-\Delta^\ast
+ V$ in terms of $L^p$-norms of the potential. Original results within the
self-adjoint framework are provided too.


  There are numerous styles of planar graph drawings, notably straight-line
drawings, poly-line drawings, orthogonal graph drawings and visibility
representations. In this note, we show that many of these drawings can be
transformed from one style to another without changing the height of the
drawing. We then give some applications of these transformations.


  In their seminal paper in the ACM Transactions on Software Engineering and
Methodology, Zave and Jackson established a core ontology for Requirements
Engineering (RE) and used it to formulate the "requirements problem", thereby
defining what it means to successfully complete RE. Given that stakeholders of
the system-to-be communicate the information needed to perform RE, we show that
Zave and Jackson's ontology is incomplete. It does not cover all types of basic
concerns that the stakeholders communicate. These include beliefs, desires,
intentions, and attitudes. In response, we propose a core ontology that covers
these concerns and is grounded in sound conceptual foundations resting on a
foundational ontology. The new core ontology for RE leads to a new formulation
of the requirements problem that extends Zave and Jackson's formulation. We
thereby establish new standards for what minimum information should be
represented in RE languages and new criteria for determining whether RE has
been successfully completed.


  The BCF theory of crystal growth has been successful in describing a wide
range of phenomena in surface physics. Typical crystal surfaces are slightly
misoriented with respect to a facet plane; thus, the BCF theory views such
systems as composed of staircase-like structures of steps separating terraces.
Adsorbed atoms (adatoms), which are represented by a continuous density,
diffuse on terraces, and steps move by absorbing or emitting these adatoms.
Here we shed light on the microscopic origins of the BCF theory by deriving a
simple, one-dimensional (1D) version of the theory from an atomistic, kinetic
restricted solid-on- solid (KRSOS) model without external material deposition.
We define the time-dependent adatom density and step position as appropriate
ensemble averages in the KRSOS model, thereby exposing the non-equilibrium
statistical mechanics origins of the BCF theory. Our analysis reveals that the
BCF theory is valid in a low adatom-density regime, much in the same way that
an ideal gas approximation applies to dilute gasses. We find conditions under
which the surface remains in a low-density regime and discuss the microscopic
origin of corrections to the BCF model.


  We discuss the leading-logarithmic power corrections in the $N$-jettiness
subtraction scheme for higher-order perturbative QCD calculations. We compute
the next-to-leading order power corrections for an arbitrary $N$-jet process,
and we explicitly calculate the power correction through
next-to-next-to-leading order for color-singlet production for both $q\bar{q}$
and $gg$ initiated processes. Our results are compact and simple to implement
numerically. Including the leading power correction in the $N$-jettiness
subtraction scheme substantially improves its numerical efficiency. We discuss
what features of our techniques extend to processes containing final-state
jets.


  We show that, if $f$ is a homeomorphism of the 2--torus isotopic to the
identity, and its lift $\widetilde f$ is transitive, or even if it is
transitive outside of the lift of the elliptic islands, then $(0,0)$ is in the
interior of the rotation set of $\widetilde f.$ This proves a particular case
of Boyland's conjecture.


  We investigate the spreading properties of a three-species
competition-diffusion system, which is non-cooperative. We apply the
Hamilton-Jacobi approach, due to Freidlin, Evans and Souganidis, to establish
upper and lower estimates of spreading speed of the slowest species, in terms
of the spreading speed of two faster species, and show that the estimates are
sharp in some situations. The spreading speed will first be characterized as
the free boundary point of the viscosity solution for certain variational
inequality cast in the space of speeds. Its exact formulas will then be derived
by solving the variational inequality explicitly. To the best of our knowledge,
this is the first theoretical result on three-species competition system in
unbounded domains.


  This work reports on high resolution photoelectron spectroscopy for the
valence band of Co2Mn(1-x)Fe(x)Si (x=0,0.5,1) excited by photons of about 8 keV
energy. The measurements show a good agreement to calculations of the
electronic structure using the LDA+U scheme. It is shown that the high energy
spectra reveal the bulk electronic structure better compared to low energy XPS
spectra. The high resolution measurements of the valence band close to the
Fermi energy indicate the existence of the gap in the minority states for all
three alloys.


  Capillary electrophoresis has long been been recognized as a powerful
analytic tool. Here it is demonstrated that the same capillary electrophoretic
experiments also reveal dynamic properties of the polymer solutions being used
as the support medium. The dependence of the electrophoretic mobility on the
size of the probe and the properties of the matrix polymers shows a unity of
behavior between electrophoresis and other methods of studying polymer
properties.


  For several classes of mathematical models that yield linear systems, the
splitting of the matrix into its Hermitian and skew Hermitian parts is
naturally related to properties of the underlying model. This is particularly
so for discretizations of dissipative Hamiltonian ODEs, DAEs and port
Hamiltonian systems where, in addition, the Hermitian part is positive definite
or semi-definite. It is then possible to develop short recurrence optimal
Krylov subspace methods in which the Hermitian part is used as a
preconditioner. In this paper we develop new, right preconditioned variants of
this approach which as their crucial new feature allow the systems with the
Hermitian part to be solved only approximately in each iteration while keeping
the short recurrences. This new class of methods is particularly efficient as
it allows, for example, to use few steps of a multigrid solver or a
(preconditioned) CG method for the Hermitian part in each iteration. We
illustrate this with several numerical experiments for large scale systems.


  The detection of online cyberbullying has seen an increase in societal
importance, popularity in research, and available open data. Nevertheless,
while computational power and affordability of resources continue to increase,
the access restrictions on high-quality data limit the applicability of
state-of-the-art techniques. Consequently, much of the recent research uses
small, heterogeneous datasets, without a thorough evaluation of applicability.
In this paper, we further illustrate these issues, as we (i) evaluate many
publicly available resources for this task and demonstrate difficulties with
data collection. These predominantly yield small datasets that fail to capture
the required complex social dynamics and impede direct comparison of progress.
We (ii) conduct an extensive set of experiments that indicate a general lack of
cross-domain generalization of classifiers trained on these sources, and openly
provide this framework to replicate and extend our evaluation criteria.
Finally, we (iii) present an effective crowdsourcing method: simulating
real-life bullying scenarios in a lab setting generates plausible data that can
be effectively used to enrich real data. This largely circumvents the
restrictions on data that can be collected, and increases classifier
performance. We believe these contributions can aid in improving the empirical
practices of future research in the field.


  In this paper we study the long time behavior for a semilinear wave equation
with space-dependent and nonlinear damping term. After rewriting the equation
as a first order system, we define a class of approximate solutions that employ
tipical tools of hyperbolic systems of conservation laws, such as the Riemann
problem. By recasting the problem as a discrete-time nonhomogeneous system,
which is related to a probabilistic interpretation of the solution, we provide
a strategy to study its long-time behavior uniformly with respect to the mesh
size parameter $\Delta x=1/N\to 0$. The proof makes use of the Birkhoff
decomposition of doubly stochastic matrices and of accurate estimates on the
iteration system as $N\to\infty$.
  Under appropriate assumptions on the nonlinearity, we prove the exponential
convergence in $L^\infty$ of the solution to the first order system towards a
stationary solution, as $t\to+\infty$, as well as uniform error estimates for
the approximate solutions.


  Massive stars play critical roles for the reionization of the Universe.
Individual massive stars at the reionization epoch (z > 6) are too faint to
observe and quantify their contributions to reionization. Some massive stars,
however, explode as superluminous supernovae (SLSNe) or pair-instability
supernovae (PISNe) that are luminous enough to observe even at z > 6 and allow
for the direct characterization of massive star properties at the reionization
epoch. In addition, hypothetical long-sought-after PISNe are expected to be
present preferentially at high redshifts, and their discovery will have a
tremendous impact on our understanding of massive star evolution and the
formation of stellar mass black holes. The near-infrared Wide Field Instrument
on Nancy Grace Roman Space Telescope will excel at discovering such rare
high-redshift supernovae. In this work, we investigate the best survey strategy
to discover and identify SLSNe and PISNe at z > 6 with Roman. We show that the
combination of the F158 and F213 filters can clearly separate both SLSNe and
PISNe at z > 6 from nearby supernovae through their colors and magnitudes. The
limiting magnitudes are required to be 27.0 mag and 26.5 mag in the F158 and
F213 filters, respectively, to identify supernovae at z > 6. If we conduct a 10
deg2 transient survey with these limiting magnitudes for 5 years with a cadence
of one year, we expect to discover 22.5 +- 2.8 PISNe and 3.1 +- 0.3 SLSNe at z
> 6, depending on the cosmic star-formation history. The same survey is
estimated to discover 76.1 +- 8.2 PISNe and 9.1 +- 0.9 SLSNe at 5 < z < 6. Such
a supernova survey requires the total observational time of approximately 525
hours in 5 years. The legacy data acquired with the survey will also be
beneficial for many different science cases including the study of
high-redshift galaxies.


  Based on the formulated and proven similarity properties of cosmological
models based on a statistical system of degenerate scalarly charged fermions,
as well as the previously identified mechanism of scalar-gravitational
instability of cosmological models, a numerical-analytical study of the
formation of supermassive black hole nuclei in the early Universe was carried
out. A mathematical model of the evolution of spherical perturbations is
constructed, on the basis of which the main regularities of the process of
evolution of collapsing masses and the dependence of the parameters of forming
black holes on the fundamental parameters of the cosmological model and the
wavelength of gravitational perturbations are revealed. In this case, the mass
loss of the black hole due to quantum evaporation is taken into account. A
stable tendency for the early formation of supermassive black hole nuclei in
the class of cosmological models under study is shown, and a close connection
between the growth of masses of spherical perturbations and the nature of the
singular points of these models is shown. Keywords: scalarly charged plasma,
cosmological model, Higgs scalar field, gravitational stability, spherical
perturbations, black hole formation, evaporation.


  Dynamical systems are no strangers in wireless communications. Our story will
necessarily involve chaos, but not in the terms secure chaotic communications
have introduced it: we will look for the chaos, complexity and dynamics that
already exist in everyday wireless communications. We present a short overview
of dynamical systems and chaos before focusing on the applications of dynamical
systems theory to wireless communications in the past 30 years, ranging from
the modeling on the physical layer to different kinds of self-similar traffic
encountered all the way up to the network layer. The examples of past research
and its implications are grouped and mapped onto the media layers of ISO OSI
model to show just how ubiquitous dynamical systems theory can be and to trace
the paths that may be taken now. When considering the future paths, we argue
that the time has come for us to revive the interest in dynamical systems for
wireless communications. It did not happen already because of the big question:
can we afford observing systems of our interest as dynamical systems and what
are the trade-offs? The answers to these questions are dynamical systems of its
own: they change not only with the modeling context, but also with time. In the
current moment the available resources allow such approach and the current
demands ask for it. Reservoir computing, the major player in dynamical
systems-related learning originated in wireless communications, and to wireless
communications it should return.


  Using a data sample corresponding to an integrated luminosity of 567
pb$^{-1}$ collected at a center-of-mass energy of $\sqrt{s}=4.6$ GeV with the
BESIII detector, we measure the absolute branching fraction of the inclusive
semileptonic $\Lambda_c^+$ decay with a double-tag method. We obtain
$\mathcal{B}(\Lambda_c^+ \rightarrow X e^+ \nu_e) = (3.95\pm0.34\pm0.09)\%$,
where the first uncertainty is statistical and the second systematic. Using the
known $\Lambda_c^+$ lifetime and the charge-averaged semileptonic decay width
of nonstrange charmed measons ($D^0$ and $D^+$), we obtain the ratio of the
inclusive semileptonic decay widths $\Gamma(\Lambda_c^+ \rightarrow X e^+
\nu_e)/\bar{\Gamma}(D\rightarrow X e^+ \nu_e)= 1.26\pm0.12$.


  Let $\Omega$ be an open, bounded domain in the plane with connected and
smooth boundary, and $\omega$ an eigenfunction of the Neumann Laplacian
corresponding to some Neumann eigenvalue $\mu > 0$. If the boundary value of
$\omega$ is a nonzero constant along the boundary, denoting $0 = \mu_1(\Omega)
< \mu_2(\Omega) <= ...$ the set of all Neumann eigenvalues for the Laplacian on
$\Omega$, we show that 1) if $\mu < \mu_8(\Omega)$; or 2) if $\Omega$ is
strictly convex and centrally symmetric, $\mu < \mu_13(\Omega)$, then $\Omega$
must be a disk.


  In this paper we construct the Quantum Gau\ss Jordan Elimination (QGJE)
Algorithm and estimate the complexity time of computation of Reduced Row
Echelon Form (RREF) of an $N\times N$ matrix using QGJE procedure. The main
theorem asserts that QGJE has computation time of order $2^{N/2}$.


  We consider eigenfunctions of the Laplace-Beltrami operator on special
surfaces of revolution. For this separable system, the nodal domains of the
(real) eigenfunctions form a checker-board pattern, and their number $\nu_n$ is
proportional to the product of the angular and the "surface" quantum numbers.
Arranging the wave functions by increasing values of the Laplace-Beltrami
spectrum, we obtain the nodal sequence, whose statistical properties we study.
In particular we investigate the distribution of the normalized counts
$\frac{\nu_n}{n}$ for sequences of eigenfunctions with $K \le n\le K + \Delta
K$ where $K,\Delta K \in \mathbb{N}$. We show that the distribution approaches
a limit as $K,\Delta K\to\infty$ (the classical limit), and study the leading
corrections in the semi-classical limit. With this information, we derive the
central result of this work: the nodal sequence of a mirror-symmetric surface
is sufficient to uniquely determine its shape (modulo scaling).


  We present news proofs of the additivity, resolution and cofinality theorems
for the algebraic $K$-theory of exact categories. These proofs are entirely
algebraic, based on Grayson's presentation of higher algebraic $K$-groups via
binary complexes.


  The dynamics of the complete breakup process in an Ortho Ps - He+ system
including electron loss to the continuum (ELC) is studied where both the
projectile and the target get ionized. The process is essentially a four body
problem and the present model takes account of the two centre effect on the
electron ejected from the Ps atom which is crucial for a proper description of
the ELC phenomena. The calculations are performed in the framework of Coulomb
Distorted Eikonal Approximation. The exchange effect between the target and the
projectile electron is taken into account in a consistent manner. The proper
asymptotic 3-body boundary condition for this ionization process is also
satisfied in the present model. A distinct broad ELC peak is noted in the fully
differential cross sections (5DCS) for the Ps electron corroborating
qualitatively the experiment for the Ps - He system. Both the dynamics of the
ELC from the Ps and the ejected electron from the target He+ in the FDCS are
studied using coplanar geometry. Interesting features are noted in the FDCS for
both the electrons belonging to the target and the projectile.


  In this paper we prove that if two normal affine surfaces $S$ and $S'$ have
isomorphic automorphism groups, then every connected algebraic group acting
regularly and faithfully on $S$ acts also regularly and faithfully on $S'$.
Moreover, if $S$ is non-toric, we show that the dynamical type of a 1-torus
action is preserved in presence of an additive group action. We also show that
complex affine toric surfaces are determined by the abstract group structure of
their regular automorphism groups in the category of complex normal affine
surfaces using properties of the Cremona group. As a generalization to
arbitrary dimensions, we show that complex affine toric varieties, with the
exception of the algebraic torus, are uniquely determined in the category of
complex affine normal varieties by their automorphism groups seen as
ind-groups.


  This paper fires the opening salvo in the systematic construction of the
lattice-continuum correspondence, a precise dictionary that describes the
emergence of continuum quantum theories from finite, nonperturbatively defined
models ("lattice theories"). Here the focus will be on quantum field theory in
(0+1)D, i.e. quantum mechanics. The main conceptual achievement is an explicit
and systematic procedure for reducing a theory with a large but finite Hilbert
space to a subtheory in which wavefunctions satisfy prescribed smoothness and
compactness constraints. This reduction, here named taming, in effect defines
quantum mechanics on a continuum target space. When appropriate lattice
theories are tamed, many familiar continuum notions explicitly emerge, e.g.
canonical commutation relations, contact terms in correlation functions,
continuous spacetime symmetries, and supersymmetry algebras. All of these are
thus "put on the lattice" using the present framework. This analysis also leads
to further insights into old subjects: for example, it is proven that any
supersymmetric lattice theory must have a vanishing Witten index.


  In this study we introduce a new technique for symbolic regression that
guarantees global optimality. This is achieved by formulating a mixed integer
non-linear program (MINLP) whose solution is a symbolic mathematical expression
of minimum complexity that explains the observations. We demonstrate our
approach by rediscovering Kepler's law on planetary motion using exoplanet data
and Galileo's pendulum periodicity equation using experimental data.


  This paper is concerned with the initial-boundary value problem for the
Einstein equations in a first-order generalized harmonic formulation. We impose
boundary conditions that preserve the constraints and control the incoming
gravitational radiation by prescribing data for the incoming fields of the Weyl
tensor. High-frequency perturbations about any given spacetime (including a
shift vector with subluminal normal component) are analyzed using the
Fourier-Laplace technique. We show that the system is boundary-stable. In
addition, we develop a criterion that can be used to detect weak instabilities
with polynomial time dependence, and we show that our system does not suffer
from such instabilities. A numerical robust stability test supports our claim
that the initial-boundary value problem is most likely to be well-posed even if
nonzero initial and source data are included.


  We show that the spin-orbit interaction (SOI) produced by the Coulomb fields
of charged impurities provides an efficient mechanism for the bound states
formation. The mechanism can be realized in 2D materials with sufficiently
strong Rashba SOI provided that the impurity locally breaks the structure
inversion symmetry in the direction normal to the layer.


  The development of quantum algorithms to solve quantum chemistry problems has
offered a promising new paradigm of performing computer simulations at the
scale of atoms and molecules. Although majority of the research so far has
focused on designing quantum algorithms to compute ground and excited state
energies and forces, it is useful to run different simulation tasks, such as
geometry optimization, with these algorithms as subroutines. Towards this end,
we have created an interface for the Variational Quantum Eigensolver based
molecular Energy (VQE-E) and molecular Force (VQE-F) code to the Atomic
Simulation Environment (ASE). We demonstrate the working of this hybrid
quantum-classical interface by optimizing the geometry of water molecule using
a native optimizer implemented in ASE. Furthermore, this interface enables one
to compare, combine and use quantum algorithms in conjunction with related
classical methods quite easily with minimal coding effort.


  We give a detailed study of axion-photon and photon-axion conversion
amplitudes, which enter the analysis of ``light shining through a wall''
experiments. Several different calculational methods are employed and compared,
and in all cases we retain a nonzero axion mass. To leading order, we find that
when the photon frequency $\omega$ is very close to the axion mass $m$, there
is a threshold cusp which significantly enhances the photon to axion conversion
amplitude, by a factor $\omega/\sqrt{\omega^2-m^2}$ relative to the
corresponding axion to photon conversion process. When $m=0$, the enhancement
factor reduces to unity and the results of previous calculations are recovered.
Our calculations include an exact wave matching analysis, which shows how
unitarity is maintained near threshold at $\omega=m$, and a discussion of the
case when the magnetic field extends into the ``wall'' region.


  In this paper, we are concerned with the existence of local isometric
embeddings into Euclidean space for analytic Riemannian metrics $g$, defined on
a domain $U\subset \mathbf{R}^n$, which are singular in the sense that the
determinant of the metric tensor is allowed to vanish at an isolated point (say
the origin). Specifically, we show that, under suitable technical assumptions,
there exists a local analytic isometric embedding $u$ from $(U',\Pi^*g)$ into
Euclidean space $\mathbf{E}^{(n^2+3n-4)/2}$, where $\Pi:U' \to
U\backslash\{0\}$ is a finite Riemannian branched cover of a deleted
neighborhood of the origin. Our result can thus be thought of as a
generalization of the classical Cartan-Janet Theorem to the singular setting in
which the metric tensor is degenerate at an isolated point. Our proof uses
Leray's ramified Cauchy-Kovalevskaya Theorem for analytic differential systems,
in the form obtained by Choquet-Bruhat for non-linear systems.


  Modern processors employ different prediction mechanisms to speculate over
different kinds of instructions. Attackers can exploit these prediction
mechanisms simultaneously in order to trigger leaks about
speculatively-accessed data. Thus, sound reasoning about such speculative leaks
requires accounting for all potential mechanisms of speculation. Unfortunately,
existing formal models only support reasoning about fixed, hard-coded
mechanisms of speculation, with no simple support to extend said reasoning to
new mechanisms.
  In this paper we develop a framework for reasoning about composed speculative
semantics that capture speculation due to different mechanisms and implement it
as part of the Spectector verification tool. We implement novel semantics for
speculating over store and return instructions and combine them with the
semantics for speculating over branches. Our framework yields speculative
semantics for speculating over any combination of those instructions that are
secure by construction, i.e., we obtain these security guarantees for free. The
implementation of our novel semantics in Spectector let us verify existing
codebases that are vulnerable to Spectre v1, Spectre v4, and Spectre v5
vulnerabilities as well as new snippets that are only vulnerable to their
compositions.


  We introduce and simulate the random walk that adapts move strategies
according to local node preferences on a directed graph. We consider graphs
with double-hierarchical connectivity and variable wiring diagram in the
universality class of the world-wide Web. The ensemble of walkers reveals the
structure of local subgraphs with dominant promoters and attractors of links.
The average access time decays with the distance in hierarchy $\Delta q$ as a
power $<t_{aw}> \sim (\Delta q)^{-\theta}$. The access to highly connected
nodes is orders of magnitude shorter compared to the standard random walk,
suggesting the adaptive walk as an efficient message-passing algorithm on this
class of graphs.


  In [6] we proved Chen's inequality regarded as a problem of constrained
maximum. In this paper we introduce a Riemannian invariant obtained from Chen's
invariant, replacing the sectional curvature by the Ricci curvature of k-order.
This invariant can be estimated, in the case of submanifolds M in space forms
$\widetilde{M}(c)$, varying with c and the mean curvature of M in
$\widetilde{M}(c)$. A improuvement of this inequality in the Lagrangian case is
obtained.


  In cybersecurity, CVEs (Common Vulnerabilities and Exposures) are publicly
disclosed hardware or software vulnerabilities. These vulnerabilities are
documented and listed in the NVD database maintained by the NIST. Knowledge of
the CVEs impacting an information system provides a measure of its level of
security. This article points out that these vulnerabilities should be
described in greater detail to understand how they could be chained together in
a complete attack scenario. This article presents the first proposal for the
CAPG format, which is a method for representing a CVE vulnerability, a
corresponding exploit, and associated attack positions.


  We explore depth measures for flow hierarchy in directed networks. We define
two measures -- rooted depth and relative depth, and discuss differences
between them. We investigate how the two measures behave in random Erdos-Renyi
graphs of different sizes and densities and explain obtained results.


  We present a new computational method by extending the Immersed Boundary (IB)
method with a spectrally-accurate geometric model based on Radial Basis
Function (RBF) interpolation of the Lagrangian structures. Our specific
motivation is the modeling of platelets in hemodynamic flows, though we
anticipate that our method will be useful in other applications as well. The
efficacy of our new RBF-IB method is shown through a series of numerical
experiments. Specifically, we compare our method with the traditional IB method
in terms of convergence and accuracy, computational cost, maximum stable
time-step size and volume loss. We conclude that the RBF-IB method has
advantages over the traditional Immersed Boundary method, and is well-suited
for modeling of platelets in hemodynamic flows.


  The present work investigates the performance parameters of low-cost &
nontoxic Mg$_{2}$Si and Ca$_{2}$Si compounds for photovoltaic (PV) applications
by using density functional theory (DFT) and spectroscopic limited maximum
efficiency (SLME) calculations. For this purpose, a detailed analysis of
electronic and optical properties has been performed by using PBE, PBEsol and
mBJ exchange-correlation functionals. The band-gap for Mg$_{2}$Si (Ca$_{2}$Si)
is found to be in the range of 0.25-0.6 (0.57-0.96) eV with an indirect (a
direct) in nature. Moreover, the density of state effective mass at top of the
valence and bottom of the conduction band is obtained to be in the range of
0.14-0.17 (1.17-1.25)m$_{e}$ and 0.27-0.29 (0.3-0.41)m$_{e}$, respectively. The
real and imaginary parts of the dielectric function show a sharp maximum of
magnitude $\sim$40 (15.6) at $\sim$2.6 (0.7) eV and $\sim$47 (14) at $\sim$2.7
(2.6) eV, respectively. Further, the highest absorption coefficient in the
solar spectrum active region is found to be $\sim$1.45 (0.8) $\times$$10^{6}$
$cm^{-1}$. The SLME with respect to the depletion width (W$_{0}$) of an ideal
single-junctional solar cell is estimated. The highest SLME at 300 K is
obtained to be $\sim$3.89 (31.21)%. The required concentrations of acceptor and
donor atoms to achieve this SLME are $\sim$10$^{18}$ $cm^{-3}$ and $\sim$0.45
(0.12) $\times 10^{16}$ $cm^{-3}$, respectively, which corresponds to a W$_{0}$
of $\sim$0.42 (0.84) $\mu m$. The present study suggests that Ca$_{2}$Si
(Mg$_{2}$Si) is a potential candidate for single-junction (bottom cell in
multi-junction) thin-film solar devices.


  We consider the problem of power allocation over a time-varying channel with
unknown distribution in energy harvesting communication systems. In this
problem, the transmitter has to choose the transmit power based on the amount
of stored energy in its battery with the goal of maximizing the average rate
obtained over time. We model this problem as a Markov decision process (MDP)
with the transmitter as the agent, the battery status as the state, the
transmit power as the action and the rate obtained as the reward. The average
reward maximization problem over the MDP can be solved by a linear program (LP)
that uses the transition probabilities for the state-action pairs and their
reward values to choose a power allocation policy. Since the rewards associated
the state-action pairs are unknown, we propose two online learning algorithms:
UCLP and Epoch-UCLP that learn these rewards and adapt their policies along the
way. The UCLP algorithm solves the LP at each step to decide its current policy
using the upper confidence bounds on the rewards, while the Epoch-UCLP
algorithm divides the time into epochs, solves the LP only at the beginning of
the epochs and follows the obtained policy in that epoch. We prove that the
reward losses or regrets incurred by both these algorithms are upper bounded by
constants. Epoch-UCLP incurs a higher regret compared to UCLP, but reduces the
computational requirements substantially. We also show that the presented
algorithms work for online learning in cost minimization problems like the
packet scheduling with power-delay tradeoff with minor changes.


  The main objective of this work is the construction of regular black hole
solutions in the context of the Einstein-Maxwell theory. The strategy is to
match an interior regular solution to an exterior electrovacuum solution. With
this purpose, we first write explicitly the Einstein field equations for the
interior regular region. We take an electrically charged nonisotropic fluid,
which presents spherical symmetry and a de Sitter type equation of state, where
the radial pressure $p_r$ is equal to the negative of energy density $\rho$,
$p_r=-\rho$. Then, two solutions for the Einstein equations are built, a
regular interior solution for the region with matter satisfying a de Sitter
equation of state, and an external solution for the region outside the matter,
that corresponds to the Reissner-Nordstr\"om metric. To complete the solution
we apply the Darmois-Israel junction conditions with a timelike thin shell at
the matching surface. It is assumed that the matching surface is composed by a
thin shell of matter, i.e., a surface layer in the form a perfect fluid obeying
a barotropic equation of state, $\mathcal{P}=\omega\sigma$, $P$ and $\sigma $
being the intrinsic pressure and energy density of the shell, respectively, and
$\omega$ a constant parameter. We show that there are electrically charged
regular black hole solutions and other compact objects for specific choices of
$\omega$ and of the other parameters of the model. Some properties of the
objects are investigated.


  Finding a feasible scheme for testing the quantum mechanical nature of the
gravitational interaction has been attracting an increasing level of attention.
Gravity mediated entanglement generation so far appears to be the key
ingredient for a potential experiment. In a recent proposal [D. Carney et al.,
Phys. Rev. X Quantum 2, 030330 (2021)] combining an atom interferometer with a
low-frequency mechanical oscillator, a coherence revival test is proposed for
verifying this entanglement generation. With measurements performed only on the
atoms, this protocol bypasses the need for correlation measurements. Here we
explore formulations of such a protocol, and specifically find that in the
envisioned regime of operation with high thermal excitation, semi-classical
models, where there is no concept of entanglement, also give the same
experimental signatures. We elucidate in a fully quantum mechanical calculation
that entanglement is not the source of the revivals in the relevant parameter
regime. We argue that, in its current form, the suggested test is only relevant
if the oscillator is nearly in a pure quantum state, and in this regime the
effects are too small to be measurable. We further discuss potential open ends.
The results highlight the importance and subtleties of explicitly considering
how the quantum case differs from the classical expectations when testing for
the quantum mechanical nature of a physical system.


  Fast radio bursts (FRBs) are mysterious millisecond-duration radio transients
of unknown origin observed at extragalactic distances. It has been long
speculated that magnetars are the engine powering repeating bursts from FRB
sources, but no convincing evidence has been collected so far\cite{sun19}.
Recently, the Galactic magnetar SGR J1935+2154 entered an active phase by
emitting intense soft Gamma-ray bursts. One FRB-like event with two peaks (FRB
200428) and a luminosity slightly lower than the faintest extragalactic FRBs
was detected from the source, in association with a soft Gamma-ray / hard X-ray
flare. Here we report an eight-hour targeted radio observational campaign
comprising four sessions and assisted by multi-wavelength (optical and hard
X-rays) data. During the third session, 29 soft Gamma-ray repeater (SGR) bursts
were detected in Gamma-ray energies. Throughout the observing period, we
detected no single dispersed pulsed emission coincident with the arrivals of
SGR bursts, but unfortunately we were not observing when the FRB was detected.
The non-detection places a fluence upper limit that is eight orders of
magnitude lower than the fluence of FRB 200428. Our results suggest that FRB --
SGR burst associations are rare. FRBs may be highly relativistic and
geometrically beamed, or FRB-like events associated with SGR bursts may have
narrow spectra and characteristic frequencies outside the observed band. It is
also possible that the physical conditions required to achieve coherent
radiation in SGR bursts are difficult to satisfy, and that only under extreme
conditions could an FRB be associated with an SGR burst.


  It is proposed that fragmentation functions should be used to identify exotic
hadrons. As an example, fragmentation functions of the scalar meson f_0(980)
are investigated. It is pointed out that the second moments and functional
forms of the u- and s-quark fragmentation functions can distinguish the
tetraquark structure from $q\bar q$. By the global analysis of f_0 (980)
production data in electron-positron annihilation, its fragmentation functions
and their uncertainties are determined. It is found that the current available
data are not sufficient to determine its internal structure, while precise data
in future should be able to identify exotic quark configurations.


  Computed Tomography (CT) takes X-ray measurements on the subjects to
reconstruct tomographic images. As X-ray is radioactive, it is desirable to
control the total amount of dose of X-ray for safety concerns. Therefore, we
can only select a limited number of measurement angles and assign each of them
limited amount of dose. Traditional methods such as compressed sensing usually
randomly select the angles and equally distribute the allowed dose on them. In
most CT reconstruction models, the emphasize is on designing effective image
representations, while much less emphasize is on improving the scanning
strategy. The simple scanning strategy of random angle selection and equal dose
distribution performs well in general, but they may not be ideal for each
individual subject. It is more desirable to design a personalized scanning
strategy for each subject to obtain better reconstruction result. In this
paper, we propose to use Reinforcement Learning (RL) to learn a personalized
scanning policy to select the angles and the dose at each chosen angle for each
individual subject. We first formulate the CT scanning process as an MDP, and
then use modern deep RL methods to solve it. The learned personalized scanning
strategy not only leads to better reconstruction results, but also shows strong
generalization to be combined with different reconstruction algorithms.


  Several quantities of interest in quantum information, including entanglement
and purity, are nonlinear functions of the density matrix and cannot, even in
principle, correspond to proper quantum observables. Any method aimed to
determine the value of these quantities should resort to indirect measurements
and thus corresponds to a parameter estimation problem whose solution, i.e the
determination of the most precise estimator, unavoidably involves an
optimization procedure. We review local quantum estimation theory and present
explicit formulas for the symmetric logarithmic derivative and the quantum
Fisher information of relevant families of quantum states. Estimability of a
parameter is defined in terms of the quantum signal-to-noise ratio and the
number of measurements needed to achieve a given relative error. The
connections between the optmization procedure and the geometry of quantum
statistical models are discussed. Our analysis allows to quantify quantum noise
in the measurements of non observable quantities and provides a tools for the
characterization of signals and devices in quantum technology.


  Recent thermal-conductivity measurements evidence a magnetic-field-induced
non-Abelian spin liquid phase in the Kitaev material
$\alpha$-$\mathrm{RuCl}_{3}$. Although the platform is a good Mott insulator,
we propose experiments that electrically probe the spin liquid's hallmark
chiral Majorana edge state and bulk anyons, including their exotic exchange
statistics. We specifically introduce circuits that exploit interfaces between
electrically active systems and Kitaev materials to `perfectly' convert
electrons from the former into emergent fermions in the latter---thereby
enabling variations of transport probes invented for topological
superconductors and fractional quantum Hall states. Along the way we resolve
puzzles in the literature concerning interacting Majorana fermions, and also
develop an anyon-interferometry framework that incorporates nontrivial
energy-partitioning effects. Our results illuminate a partial pathway towards
topological quantum computation with Kitaev materials.


  In the gravity without metric formalism of Capovilla, Jacobson and Dell, the
topological $\theta$-term appears through a canonical transformation.The origin
of this canonical transformation is probed here. It is shown here that when
$\theta$-term appears cosmological $\lambda$-term also appears simultaneously.


  In an era of increasingly advanced experimental analysis techniques it is
crucial to understand which phase space regions contribute a signal extraction
from backgrounds. Based on the Neyman-Pearson lemma we compute the maximum
significance for a signal extraction as an integral over phase space regions.
We then study to what degree boosted Higgs strategies benefit ZH and ttH
searches and which transverse momenta of the Higgs are most promising. We find
that Higgs and top taggers are the appropriate tools, but would profit from a
targeted optimization towards smaller transverse momenta. MadMax is available
as an add-on to Madgraph5.


  Deep Learning shows very good performance when trained on large labeled data
sets. The problem of training a deep net on a few or one sample per class
requires a different learning approach which can generalize to unseen classes
using only a few representatives of these classes. This problem has previously
been approached by meta-learning. Here we propose a novel meta-learner which
shows state-of-the-art performance on common benchmarks for one/few shot
classification. Our model features three novel components: First is a
feed-forward embedding that takes random class support samples (after a
customary CNN embedding) and transfers them to a better class representation in
terms of a classification problem. Second is a novel attention mechanism,
inspired by competitive learning, which causes class representatives to compete
with each other to become a temporary class prototype with respect to the query
point. This mechanism allows switching between representatives depending on the
position of the query point. Once a prototype is chosen for each class, the
predicated label is computed using a simple attention mechanism over prototypes
of all considered classes. The third feature is the ability of our meta-learner
to incorporate deeper CNN embedding, enabling larger capacity. Finally, to ease
the training procedure and reduce overfitting, we averages the top $t$ models
(evaluated on the validation) over the optimization trajectory. We show that
this approach can be viewed as an approximation to an ensemble, which saves the
factor of $t$ in training and test times and the factor of of $t$ in the
storage of the final model.


  The infrared behavior of the gluon and ghost propagators is analyzed in
Yang-Mills theories in the presence of dynamical mass generation in the Landau
gauge. By restricting the domain of integration in the path-integral to the
Gribov region $\Omega $, the gauge propagator is found to be suppressed in the
infrared, while the ghost propagator is enhanced.


  Penrose suggested that issues with the origin of the second law of
thermodynamics and the remarkable homogeneous and isotropic nature of the
universe on large scales can be resolved with a concept of an entropy for
gravitational fields captured by the Weyl curvature tensor. This has led to
various proposals for an entropy density for gravity constructed from the Weyl
tensor. Most work investigating such entropy densities have been restricted to
general relativity and little work has been done to them in modified theories
of gravity. To remedy this, we investigate the simplest proposal for an entropy
density in 5-dimensional Gauss-Bonnet gravity.