  A version of the extremal optimization (EO) algorithm introduced by Boettcher
and Percus is tested on 2D and 3D spin glasses with Gaussian disorder. EO
preferentially flips spins that are locally ``unfit''; the variant introduced
here reduces the probability to flip previously selected spins. Relative to EO,
this adaptive algorithm finds exact ground states with a speed-up of order
$10^{4}$ ($10^{2}$) for $16^{2}$- ($8^{3}$-) spin samples. This speed-up
increases rapidly with system size, making this heuristic a useful tool in the
study of materials with quenched disorder.


  This writeup is a compilation of the predictions for the forthcoming Heavy
Ion Program at the Large Hadron Collider, as presented at the CERN Theory
Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held
from May 14th to June 10th 2007.


  The Kepler satellite has discovered a number of transiting planets around
close binary stars. These circumbinary systems have highly aligned planetary
and binary orbits. In this paper, we explore how the mutual inclination between
the planetary and binary orbits may reflect the physical conditions of the
assembly of protoplanetary disks and the interaction between protostellar
binaries and circumbinary disks. Given the turbulent nature of star-forming
molecular clouds, it is possible that the gas falling onto the outer region of
a circumbinary disk and the central protostellar binary have different axes of
rotation. Thus, the newly assembled circumbinary disk can be misaligned with
respect to the binary. However, the gravitational torque from the binary
produces a warp and twist in the disk, and the back-reaction torque tends to
align the disk and the binary orbital plane. We present a new, analytic
calculation of this alignment torque, and show that the binary-disk inclination
angle can be reduced appreciably after the binary accretes a few percent of its
mass from the disk. Our calculation suggests that in the absence of other
disturbances, circumbinary disks and planets around close (sub-AU) stellar
binaries, for which mass accretion onto the proto-binary is very likely to have
occurred, are expected to be highly aligned with the binary orbits, while disks
and planets around wide binaries can be misaligned. Measurements of the mutual
inclinations of circumbinary planetary systems can provide a clue to the birth
environments of such systems.


  This work presents a complete analysis of fermion fitting and proton decay in
a SUSY $SO(10)$ model previously suggested by Dutta, Mimura, and Mohapatra.
  A key question in any grand unified theory is whether it satisfies the
experimental lower limits on proton partial lifetimes. In generic models,
substantial fine-tuning is required among GUT-scale parameters to satisfy the
limits. In the proposed model, the ${\bf 10}$, $\overline{\bf{126}}$, and ${\bf
120}$ Yukawa couplings contributing to fermion masses have restricted textures
intended to give favorable results for proton lifetime, while still giving rise
to a realistic fermion sector, without the need for fine-tuning, even for large
$\tan\beta$, and for either type-I or type-II dominance in the neutrino mass
matrix.
  In this thesis, I investigate the above hypothesis at a strict numerical
level of scrutiny; I obtain a valid fit for the entire fermion sector for both
types of seesaw dominance, including $\theta_{13}$ in good agreement with the
most recent data. For the case with type-II seesaw, I find that, using the
Yukawa couplings fixed by the successful fermion sector fit, proton partial
lifetime limits are readily satisfied for all but one of the pertinent decay
modes for nearly arbitrary values of the triplet-Higgs mixing parameters, with
the $K^+ \bar\nu$ mode requiring a ${\cal O}(10^{-1})$ cancellation in order to
satisfy its limit. I also find a maximum partial lifetime for that mode of
$\tau(K^+ \bar\nu) \sim 10^{36}\,$years. For the type-I seesaw case, I find
that $K^+ \bar\nu$ decay mode is satisfied for any values of the triplet mixing
parameters giving no major enhancement, and all other modes are easily
satisfied for arbitrary mixing values; I also find a maximum partial lifetime
for $K^+ \bar\nu$ of nearly $10^{38}\,$years, which is sub-dominant to gauge
boson decay channels.


  This paper focusses on the optimal implementation of a Mean Variance
Estimation network (MVE network) (Nix and Weigend, 1994). This type of network
is often used as a building block for uncertainty estimation methods in a
regression setting, for instance Concrete dropout (Gal et al., 2017) and Deep
Ensembles (Lakshminarayanan et al., 2017). Specifically, an MVE network assumes
that the data is produced from a normal distribution with a mean function and
variance function. The MVE network outputs a mean and variance estimate and
optimizes the network parameters by minimizing the negative loglikelihood. In
our paper, we present two significant insights. Firstly, the convergence
difficulties reported in recent work can be relatively easily prevented by
following the simple yet often overlooked recommendation from the original
authors that a warm-up period should be used. During this period, only the mean
is optimized with a fixed variance. We demonstrate the effectiveness of this
step through experimentation, highlighting that it should be standard practice.
As a sidenote, we examine whether, after the warm-up, it is beneficial to fix
the mean while optimizing the variance or to optimize both simultaneously.
Here, we do not observe a substantial difference. Secondly, we introduce a
novel improvement of the MVE network: separate regularization of the mean and
the variance estimate. We demonstrate, both on toy examples and on a number of
benchmark UCI regression data sets, that following the original recommendations
and the novel separate regularization can lead to significant improvements.


  The Elko quantum field was introduced by Ahluwalia and Grumiller, who
proposed it as a candidate for dark matter. We study the Elko field in
Weinberg's formalism for quantum field theory. We prove that if one takes the
symmetry group to be the full Poincar\'e group then the Elko field is not a
quantum field in the sense of Weinberg. This confirms results of Ahluwalia, Lee
and Schritt, who showed using a different approach that the Elko field does not
transform covariantly under rotations and hence has a preferred axis.


  The standard {\em system-plus-reservoir} approach used in the study of
dissipative systems can be meaningfully generalized to a dissipative coupling
involving the momentum, instead of the coordinate: the corresponding equation
of motion differs from the Langevin equation, so this is called {\em anomalous}
dissipation. It occurs for systems where such coupling can indeed be derived
from the physical analysis of the degrees of freedom which can be treated as a
dissipation bath. Starting from the influence functional corresponding to
anomalous dissipation, it is shown how to derive the effective classical
potential that gives the quantum thermal averages for the dissipative system in
terms of classical-like calculations; the generalization to many degrees of
freedom is given. The formalism is applied to a single particle in a
double-well and to the discrete $\phi^4$ model. At variance with the standard
case, the fluctuations of the coordinate are enhanced by anomalous dissipative
coupling.


  All members of a recently proposed new set of (non-supersymmetric) grand
unified theories with at the one-loop level vanishing beta functions for the
gauge, Yukawa, and scalar-boson self-interaction coupling constants are shown
to involve, already at the one-loop level, quadratically divergent
contributions to both the vector-boson and scalar-boson masses.


  We construct a class of projected SO(5) models where the Gutzwiller
constraint of no-double-occupancy is implemented exactly. We introduce the
concept of projected SO(5) symmetry where all static correlation functions are
exactly SO(5) symmetric and discuss the signature of the projected SO(5)
symmetry in dynamical correlation functions. We show that this class of
projected SO(5) models can give a realistic description of the global phase
diagram of the high T_c superconductors and account for many of their physical
properties.


  For more than 30 years [1], gamma-gamma and gamma-electron photon colliders
have been considered a natural addition to e+e- linear-collider projects.
Following the recent discovery of the Higgs boson, the physics community has
been actively considering various approaches to building a Higgs factory, a
photon collider (with or without e+e-) being one of them. In this note,
following a brief discuss of photon colliders based on ILC and CLIC, I give a
critical overview of the recently proposed photon-collider Higgs factories with
no e+e- collision option.


  An approximate quantum-mechanical two-body equation for spinless particles
incorporating relativistic kinematics is derived. The derivation is based on
the relativistic energy-momentum relation $mc^{2}+\epsilon =
\sqrt{m^{2}c^{4}+p^{2}c^{2}}+V$ for each single particle, where $mc^2$ is the
particle rest mass energy, $p$ its linear momentum, $\epsilon$ its dynamical
energy, and $V$ being the time-like vector interaction potential. The resulting
two-body equation assumes rapid wave oscillations in a single, slowly varying
potential well. A Bohr-Sommerfeld-type quantization condition is obtained. The
approximation is compared to exact results for the harmonic potential.


  The dipole electric ($E1$) and magnetic ($M1$) strengths in strongly deformed
$^{156}$Gd are investigated within a fully self-consistent Quasiparticle Random
Phase Approximation (QRPA) with Skyrme forces SVbas, SLy6 and SG2. We inspect,
on the same theoretical footing, low-lying dipole states and the isovector
giant dipole resonance in $E1$ channel and the orbital scissors resonance as
well as the spin-flip giant resonance (SFGR) in $M1$ channel. Besides, $E1$
toroidal mode and low-energy spin-flip $M1$ excitations are considered. The
deformation splitting and dipole-octupole coupling of electric excitations are
analyzed. The origin of SFGR gross structure, impact of the residual
interaction and interference of orbital and spin contributions to SFGR are
discussed. The effect of the central exchange $\textbf{J}^2$-term from the
Skyrme functional is demonstrated. The calculations show a satisfactory
agreement with available experimental data, except for the recent NRF
measurements of M. Tamkas et al for $M1$ strength at 4-6 MeV, where, in
contradiction with our calculations and previous $(p,p')$ data, almost no $M1$
strength was observed.


  Though pairs of dynamically associated asteroids in the Main Belt have been
identified and studied for over a decade, very few pair systems have been
identified in the near-Earth asteroid population. We present data and analysis
that supports the existence of two genetically related pairs in near-Earth
space. The members of the individual systems, 2015 EE7 -- 2015 FP124 and 2017
SN16 -- 2018 RY7, are found to be of the same spectral taxonomic class, and
both pairs are interpreted to have volatile-poor compositions. In conjunction
with dynamical arguments, this suggests that these two systems formed via YORP
spin-up and/or dissociation of a binary precursor. Backwards orbital
integrations suggest a separation age of <10 kyr for the pair 2017 SN16 -- 2018
RY7, making these objects amongst the youngest multiple asteroid systems known
to date. A unique separation age was not realized for 2015 EE7 -- 2015 FP124
due to large uncertainties associated with these objects' orbits. Determining
the ages of such young pairs is of great value for testing models of space
weathering and asteroid spin-state evolution. As the NEO catalog continues to
grow with current and future discovery surveys, it is expected that more NEO
pairs will be found, thus providing an ideal laboratory for studying time
dependent evolutionary processes that are relevant to asteroids throughout the
Solar System.


  Let Omega be a finite set and let S be a set system on Omega. For x in Omega,
we denote by d_{S}(x) the number of members of S containing x. A long-standing
conjecture of Frankl states that if S is union-closed then d(x) \geq |S|/2 for
some x in Omega. We consider a related question. Define the weight of S to be
w(S)= \sum_{A in S} |A|. Suppose S is union-closed. How small can w(S) be?
Reimer showed that w(S) \geq |S| \log_{2} |S| /2, and that this inequality is
sharp. In this paper we show how his bound may be improved if we have some
additional information about the domain Omega of S: if S separates the points
of Omega, then w(S) \geq \binom{|\Omega|}{2}. This is stronger than Reimer's
Theorem when Omega > \sqrt{|S|\log_2 |S|}. In addition we construct a family of
examples showing the combined bound on w(S) is tight except in the region
|\Omega|=\Theta (\sqrt{|S|\log_2 |S|}), where it may be off by a multiplicative
factor of 2. Our proof also gives a lower bound on the average degree: if S is
a point-separating union-closed family, then the average degree over its domain
is at least 1/2 \sqrt{|S| \log_2 |S|}+ O(1), and this is best possible except
for a multiplicative factor of 2.


  A Weyl point in a superconducting nanostructure is a generic minimum model of
a topological singularity at low energies. We connect the nanostructure to
normal leads thereby immersing the topological singularity in the continuous
spectrum of the electron states in the leads. This sets another simple and
generic model useful to comprehend the modification of low-energy singularity
in the presence of continuous spectrum. The tunnel coupling to the leads gives
rise to new low energy scale $\Gamma$ at which all topological features are
smoothed. We investigate superconducting and normal currents in the
nanostructure at this scale. We show how the tunnel currents can be used for
detection of the Weyl point. Importantly, we find that the topological charge
is not concentrated in a point but rather is spread over the parameter space in
the vicinity of the point. We introduce and compute the resulting topological
charge density. We also reveal that the pumping to the normal leads helps to
detect and investigate the topological effects in the vicinity of the point.


  Due to the ubiquity of spatial data applications and the large amounts of
spatial data that these applications generate and process, there is a pressing
need for scalable spatial query processing. In this paper, we present new
techniques for spatial query processing and optimization in an in-memory and
distributed setup to address scalability. More specifically, we introduce new
techniques for handling query skew, which is common in practice, and optimize
communication costs accordingly. We propose a distributed query scheduler that
use a new cost model to optimize the cost of spatial query processing. The
scheduler generates query execution plans that minimize the effect of query
skew. The query scheduler employs new spatial indexing techniques based on
bitmap filters to forward queries to the appropriate local nodes. Each local
computation node is responsible for optimizing and selecting its best local
query execution plan based on the indexes and the nature of the spatial queries
in that node. All the proposed spatial query processing and optimization
techniques are prototyped inside Spark, a distributed memory-based computation
system. The experimental study is based on real datasets and demonstrates that
distributed spatial query processing can be enhanced by up to an order of
magnitude over existing in-memory and distributed spatial systems.


  We propose and examine two optimal $(0,1)$-matrix completion problems with
majorization ordered objectives. They elevate the seminal study by Gale and
Ryser from feasibility to optimality in partial order programming (POP),
referring to optimization with partially ordered objectives. We showcase their
applications in electric vehicle charging, portfolio optimization, and secure
data storage. Solving such integer POP (iPOP) problems is challenging because
of the possible non-comparability among objective values and the integer
requirements. Nevertheless, we prove the essential uniqueness of all optimal
objective values and identify two particular ones for each of the two
inherently symmetric iPOP problems. Furthermore, for every optimal objective
value, we decompose the construction of an associated optimal~$(0,1)$-matrix
into a series of sorting processes, respectively agreeing with the rule of
thumb "peak shaving" or "valley filling." We show that the resulting algorithms
have linear time complexities and verify their empirical efficiency via
numerical simulations compared to the standard order-preserving method for POP.


  Bright-rimmed clouds (BRCs) are ideal candidates to study radiation-driven
implosion mode of star formation as they are potential sites of triggered star
formation, located at the edges of H{\sc ii} regions, showing evidence of
ongoing star formation processes. BRC 18 is located towards the eastern edge of
relatively closer ($\sim$400 pc) H{\sc ii} region excited by $\lambda$ Ori. We
made R-band polarimetric observations of 17 candidate young stellar objects
(YSOs) located towards BRC 18 to investigate any preferred orientation of the
discs with respect to the ambient magnetic field and the direction of energetic
photons from $\lambda$ Ori. We found that the discs are oriented randomly with
respect to the projected magnetic field. Using distances and proper motions
from the \textit{Gaia} EDR3 of the candidate YSOs, we investigated the possible
acceleration of BRC 18, away from $\lambda$ Ori due to the well known "Rocket
Effect", by assuming that both the candidate YSOs and BRC 18 are kinematically
coupled. The relative proper motions of the candidate YSOs are found to show a
trend of moving away from $\lambda$ Ori. We computed the offset between the
angle of the direction of the ionization front and the relative proper motion
of the candidate YSOs and found it to lie close to being parallel to each
other. Additionally, we found 12 sources that are comoving with the known
candidate YSOs towards BRC 18. These comoving sources are most likely to be
young and are missed in previous surveys conducted to identify potential YSOs
of the region.


  Due to the adjustable geometry, pintle injectors are specially suitable for
the liquid rocket engines which require a widely throttleable range. While
applying the conventional computational fluid dynamics approaches to simulate
the complex spray phenomena in the whole range still remains to be a great
challenge. In this paper, a novel deep learning approach used to simulate
instantaneous spray fields under continuous operating conditions is explored.
Based on one specific type of neural networks and the idea of physics
constraint, a Generative Adversarial Networks with Physics Evaluators (GAN-PE)
framework is proposed. The geometry design and mass flux information are
embedded as the inputs. After the adversarial training between the generator
and discriminator, the generated field solutions are fed into the two physics
evaluators. In this framework, mass conversation evaluator is designed to
improve the training robustness and convergence. And the spray angle evaluator,
which is composed of a down-sampling CNN and theoretical model, guides the
networks generating the spray solutions more according with the injection
conditions. The characterization of the simulated spray, including the spray
morphology, droplet distribution and spray angle, is well predicted. The work
suggests a great potential of the prior physics knowledge employment in the
simulation of instantaneous flow fields.


  Accurate background estimation is essential for spectral and temporal
analysis in astrophysics. In this work, we construct the in-orbit background
model for the High-Energy Telescope (HE) of the Hard X-ray Modulation Telescope
(dubbed as Insight-HXMT). Based on the two-year blank sky observations of
Insight-HXMT/HE, we first investigate the basic properties of the background
and find that both the background spectral shape and intensity have long-term
evolution at different geographical sites. The entire earth globe is then
divided into small grids, each with a typical area of 5x5 square degrees in
geographical coordinate system. For each grid, an empirical function is used to
describe the long-term evolution of each channel of the background spectrum;
the intensity of the background can be variable and a modification factor is
introduced to account for this variability by measuring the contemporary flux
of the blind detector. For a given pointing observation, the background model
is accomplished by integrating over the grids that are passed by the track of
the satellite in each orbit. Such a background model is tested with both the
blank sky observations and campaigns for observations of a series of celestial
sources. The results show an average systematic error of 1.5% for the
background energy spectrum (26-100 keV) under a typical exposure of 8 ks, and
<3% for background light curve estimation (30-150 keV). Therefore, the
background model introduced in this paper is included in the Insight-HXMT
software as a standard part specialized for both spectral and temporal
analyses.


  HST images of the western hot spot of the nearby FRII radio galaxy Pictor A
resolve the hot spot into an amorphous region of highly polarized wisps. The
high polarization (>~ 50%) indicates that the optical emission is synchrotron
radiation and that the magnetic field structure has been well resolved. The
magnetic field is oriented nearly perpendicular to the jet axis and apparently
very uniform. We interpret these observations in terms of a compressed magnetic
field at the working surface where the jet impinges on the intergalactic medium
some 100 kpc from the nucleus of the host galaxy.
  Keywords: Polarization --- radiation mechanisms: nonthermal --- galaxies:
active --- galaxies: individual: Pictor A --- galaxies: jets.


  A geometric first-order axiomatization of differentially closed fields of
characteristic zero with several commuting derivations, in the spirit of
Pierce-Pillay, is formulated in terms of a relative notion of prolongation for
Kolchin-closed sets.


  In this work we advocate a set of novel azimuthal-angle-related observables
associated with exclusive hadron production from two-photon fusion at $e^+ e^-$
colliders, taking the $\gamma\gamma\to \pi\pi$ as a benchmark process. As a
direct consequence of the linearly polarized quasi-real photons emitted off the
electron and positron beams, the $\cos 2\phi$ azimuthal asymmetry in dipion
production is predicted within the transverse-momentum-dependent (TMD)
factorization framework. In numerical analysis, we take the helicity amplitudes
of $\gamma\gamma\to \pi\pi$ determined from the partial wave solutions in
dispersion relation as input, and find that the predicted $\cos2\phi$ azimuthal
modulation may reach 40\% for the typical kinematical setup of {\tt Belle}
experiment. Future accurate measurement of this azimuthal asymmetry may
facilitate the direct extraction of the relative phase between two helicity
amplitudes with photon helicity configurations $++$ and $+-$. This knowledge
provides a valuable input for the dispersive determination of the hadronic
light-by-light (Hlbl) contributions, which constitutes one of the largest
theoretical uncertainties in predictions for the muon anomalous magnetic
moment.


  We give a unified statement and proof of a class of wellknown mean value
inequalities for nonnegative functions with a nonlinear bound on the Laplacian.
We generalize these to domains with boundary, requiring a (possibly nonlinear)
bound on the normal derivative at the boundary. These inequalities give rise to
an energy quantization principle for sequences of solutions of boundary value
problems that have bounded energy and whose energy densities satisfy nonlinear
bounds on the Laplacian and normal derivative: One obtains local uniform bounds
on the complement of finitely many points, where some minimum quantum of energy
concentrates.


  Solar gravity modes (or g modes) -- oscillations of the solar interior for
which buoyancy acts as the restoring force -- have the potential to provide
unprecedented inference on the structure and dynamics of the solar core,
inference that is not possible with the well observed acoustic modes (or p
modes). The high amplitude of the g-mode eigenfunctions in the core and the
evanesence of the modes in the convection zone make the modes particularly
sensitive to the physical and dynamical conditions in the core. Owing to the
existence of the convection zone, the g modes have very low amplitudes at
photospheric levels, which makes the modes extremely hard to detect. In this
paper, we review the current state of play regarding attempts to detect g
modes. We review the theory of g modes, including theoretical estimation of the
g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the
techniques that have been used to try to detect g modes. We review results in
the literature, and finish by looking to the future, and the potential advances
that can be made -- from both data and data-analysis perspectives -- to give
unambiguous detections of individual g modes. The review ends by concluding
that, at the time of writing, there is indeed a consensus amongst the authors
that there is currently no undisputed detection of solar g modes.


  We suggest two grand unified models where the fifth dimensional coordinate is
compactified on an $S_1/(Z_2 \times Z_2')$ orbifold.


  In this thesis, we study two problems based on clustering algorithms. In the
first problem, we study the role of visual attributes using an agglomerative
clustering algorithm to whittle down the search area where the number of
classes is high to improve the performance of clustering. We observe that as we
add more attributes, the clustering performance increases overall. In the
second problem, we study the role of clustering in aggregating templates in a
1:N open set protocol using multi-shot video as a probe. We observe that by
increasing the number of clusters, the performance increases with respect to
the baseline and reaches a peak, after which increasing the number of clusters
causes the performance to degrade. Experiments are conducted using recently
introduced unconstrained IARPA Janus IJB-A, CS2, and CS3 face recognition
datasets.


  Quantum(-inspired) annealers show promise in solving combinatorial
optimisation problems in practice. There has been extensive researches
demonstrating the utility of D-Wave quantum annealer and quantum-inspired
annealer, i.e., Fujitsu Digital Annealer on various applications, but few works
are comparing these platforms. In this paper, we benchmark quantum(-inspired)
annealers with three combinatorial optimisation problems ranging from generic
scientific problems to complex problems in practical use. In the case where the
problem size goes beyond the capacity of a quantum(-inspired) computer, we
evaluate them in the context of decomposition. Experiments suggest that both
annealers are effective on problems with small size and simple settings, but
lose their utility when facing problems in practical size and settings.
Decomposition methods extend the scalability of annealers, but they are still
far away from practical use. Based on the experiments and comparison, we
discuss the advantages and limitations of quantum(-inspired) annealers, as well
as the research directions that may improve the utility and scalability of the
these emerging computing technologies.


  We fabricated ferroelectric Bi4Ti3O12 (BiT) single crystalline thin films
site-specifically substituted with LaTMO3 (TM = Al, Ti, V, Cr, Mn, Co, and Ni)
on SrTiO3 substrates by pulsed laser epitaxy. When transition metals are
incorporated into a certain site of the BiT, some of BiT-LaTMO3 showed a
substantially decreased band gap, coming from the additional optical transition
between oxygen 2p and TM 3d states. Specifically, all alloys with Mott
insulators revealed a possibility of band gap reduction. Among them, BiT-LaCoO3
showed the largest band gap reduction by ~1 eV, positioning itself as a
promising material for highly efficient opto-electronic devices.


  We predict the neutrino-nucleon cross section at ultrahigh energies relevant
in connection with the search for high-energy cosmic neutrinos. Our
investigation, employing the color-dipole picture, among other things allows us
to quantitatively determine which fraction of the ultrahigh-energy
neutrino-nucleon cross section stems from the saturation versus the
color-transparency region. We disagree with various results in the literature
that predict a strong suppression of the neutrino-nucleon cross section at
neutrino energies above $E \cong 10^9 GeV$. Suppression in the sense of a
diminished increase of the neutrino-nucleon cross section with energy only
starts to occur at neutrino energies beyond $E \cong 10^{14} GeV$.


  Initialization plays a critical role in the training of deep neural networks
(DNN). Existing initialization strategies mainly focus on stabilizing the
training process to mitigate gradient vanish/explosion problems. However, these
initialization methods are lacking in consideration about how to enhance
generalization ability. The Information Bottleneck (IB) theory is a well-known
understanding framework to provide an explanation about the generalization of
DNN. Guided by the insights provided by IB theory, we design two criteria for
better initializing DNN. And we further design a neuron campaign initialization
algorithm to efficiently select a good initialization for a neural network on a
given dataset. The experiments on MNIST dataset show that our method can lead
to a better generalization performance with faster convergence.


  The family of pointillist multitarget tracking filters is defined to be the
class of filters that is characterized by a joint target-measurement finite
point process. The probability generating functional (PGFL) of the joint
process is derived directly from the probabilistic structure of the tracking
problem. PGFLs exemplify the analytic combinatoric method applied to the
measurement to target assignment problems that are fundamental to the tracking
problem. It is shown that multi-hypothesis tracking (MHT), joint probabilistic
data association (JPDA), and many other now-classic tracking filters can be
derived via PGFLs, and thus are members of the family of pointillist filters.
When one or more of the target processes are dimensionally compatible, targets
can be superposed. It is shown that the classic MHT filter for superposed
targets is closely related to the multi-Bernoulli filter. A technique is
presented for deriving the functional derivatives by ordinary differentiation,
and both exact and approximate methods for evaluating the ordinary derivatives
are discussed.


  An extensive calorimetric study of the normal- and superconducting-state
properties of Ba(Fe1-xCox)2As2 is presented for 0 < x < 0.2. The normal-state
Sommerfeld coefficient increases (decreases) with Co doping for x < 0.06 (x >
0.06), which illustrates the strong competition between magnetism and
superconductivity to monopolize the Fermi surface in the underdoped region and
the filling of the hole bands for overdoped Ba(Fe1-xCox)2As2. All
superconducting samples exhibit a residual electronic density of states of
unknown origin in the zero-temperature limit, which is minimal at optimal
doping but increases to the normal-state value in the strongly under- and
over-doped regions. The remaining specific heat in the superconducting state is
well described using a two-band model with isotropic s-wave superconducting
gaps.


  A fifth--order nonlinear partial differential equation for the description of
nonlinear waves in a liquid with gas bubbles is considered. Special solutions
of this equation are studied. Some elliptic and simple periodic traveling waves
solution are constructed. Connection of self--similar solutions with Painleve
transcendents and their high--order analogous is discussed.


  The spin echo techniques aim at the elimination of the effect of a random
magnetic field on the spin evolution. These techniques conventionally utlize
the application of a permanent field which is much stronger than the random
one. The strong field, however, may also modify the magnetic response of the
medium containing the spins, thus altering their ``natural'' dynamics. We
suggest an iterative scheme for generating a sequence of pulses which create an
echo without an external permanent field. The approximation to the ideal echo
improves with the sequence length.


  Event Horizon Telescope (EHT) observations have revealed a bright ring of
emission around the supermassive black hole at the center of the M87 galaxy.
EHT images in linear polarization have further identified a coherent spiral
pattern around the black hole, produced from ordered magnetic fields threading
the emitting plasma. Here, we present the first analysis of circular
polarization using EHT data, acquired in 2017, which can potentially provide
additional insights into the magnetic fields and plasma composition near the
black hole. Interferometric closure quantities provide convincing evidence for
the presence of circularly polarized emission on event-horizon scales. We
produce images of the circular polarization using both traditional and newly
developed methods. All methods find a moderate level of resolved circular
polarization across the image ($\langle|v|\rangle < 3.7\%$), consistent with
the low image-integrated circular polarization fraction measured by the ALMA
array ($|v_{\rm int}| < 1\%$). Despite this broad agreement, the methods show
substantial variation in the morphology of the circularly polarized emission,
indicating that our conclusions are strongly dependent upon the imaging
assumptions because of the limited baseline coverage, uncertain telescope gain
calibration, and weakly polarized signal. We include this upper limit in an
updated comparison to general relativistic magnetohydrodynamic (GRMHD)
simulation models. This analysis reinforces the previously reported preference
for magnetically arrested accretion flow models. We find that most simulations
naturally produce a low level of circular polarization consistent with our
upper limit, and that Faraday conversion is likely the dominant production
mechanism for circular polarization at 230 GHz in M87*.


  The projected entangled pair state (PEPS) representation of quantum states on
two-dimensional lattices induces an entanglement based hierarchy in state
space. We show that the lowest levels of this hierarchy exhibit an enormously
rich structure including states with critical and topological properties as
well as resonating valence bond states. We prove, in particular, that coherent
versions of thermal states of any local 2D classical spin model correspond to
such PEPS, which are in turn ground states of local 2D quantum Hamiltonians.
This correspondence maps thermal onto quantum fluctuations, and it allows us to
analytically construct critical quantum models exhibiting a strict area law
scaling of the entanglement entropy in the face of power law decaying
correlations. Moreover, it enables us to show that there exist PEPS within the
same class as the cluster state, which can serve as computational resources for
the solution of NP-hard problems.


  We developed and validated an instrument to measure the perceived readability
in data visualization: PREVis. Researchers and practitioners can easily use
this instrument as part of their evaluations to compare the perceived
readability of different visual data representations. Our instrument can
complement results from controlled experiments on user task performance or
provide additional data during in-depth qualitative work such as design
iterations when developing a new technique. Although readability is recognized
as an essential quality of data visualizations, so far there has not been a
unified definition of the construct in the context of visual representations.
As a result, researchers often lack guidance for determining how to ask people
to rate their perceived readability of a visualization. To address this issue,
we engaged in a rigorous process to develop the first validated instrument
targeted at the subjective readability of visual data representations. Our
final instrument consists of 11 items across 4 dimensions: understandability,
layout clarity, readability of data values, and readability of data patterns.
We provide the questionnaire as a document with implementation guidelines on
osf.io/9cg8j. Beyond this instrument, we contribute a discussion of how
researchers have previously assessed visualization readability, and an analysis
of the factors underlying perceived readability in visual data representations.


  The stability and approximation properties of transfer functions of
generalized Bessel polynomials (GBP) are investigated. Sufficient conditions
are established for the GBP to be Hurwitz. It is shown that the Pad\'e
approximants of $e^{-s}$ are related to the GBP.
  An infinite subset of stable Pad\'e functions useful for approximating a
constant time delay is defined and its approximation properties examined. The
lowpass Pad\'e functions are compared with an approximating function suggested
by Budak. Basic limitations of Budak's approximation are derived.


  We consider the higher order gravity with dilaton and with the leading string
theory corrections taken into account. The domain wall type solutions are
investigated for arbitrary number of space-time dimensions. The explicit
formulae for the fixed points and asymptotic behavior of generic solutions are
given. We analyze and classify solutions with finite effective gravitational
constant. There is a class of such solutions which have no singularities. We
discuss in detail the relation between fine tuning and self tuning and clarify
in which sense our solutions are fine-tuning free. The stability of such
solutions is also discussed.


  Experimental challenges in identifying various types of magnetic ordering in
graphene quantum dots (QDs) pose a major hurdle in the application of these
nanostructures for spintronic devices. }Based upon phase diagrams obtained by
employing {\normalsize{}the $\pi$-electron }Pariser-Parr-Pople (PPP) model
Hamiltonian, we demonstrate that the magnetic states undergo phase transition
under the influence of an external electric field. Our calculations of the
electro-absorption spectra of these QDs indicate that the spectrum in question
carries strong signatures of their magnetic state (FM vs AFM), thus suggesting
the possibility of an all-optical characterization of their magnetic nature.
Further, the gaps for the up and the down spins are the same in the absence of
an external electric field, both for the antiferromagnetic (AFM), and the
ferromagnetic (FM) states of QDs. But, once the QDs are exposed to a suitably
directed external electric field, gaps for different spins split, and, exhibit
distinct variations with respect to the strength of the field. The nature of
variation exhibited by the energy gaps corresponding to the up and down spins
is different for the AFM and FM configurations of QDs. This selective
manipulation of the spin-polarized gap splitting by an electric field in finite
graphene nanostructures can open up new frontiers in the design of
graphene-based spintronic devices.


  Habitability of an exoplanet is believed to be profoundly affected by
activities of the host stars, although the related coronal mass ejections
(CMEs) are still rarely detected in solar-like and late-type stars. We here
report an observational study on flares of two M-dwarfs triggered by the
high-cadence survey performed by the Ground Wide-angle Camera system. In both
events, the fast, time-resolved spectroscopy enables us to identify symmetric
broad H$\alpha$ emission with not only a nearly zero bulk velocity, but also a
large projected maximum velocity as high as $\sim700-800\ \mathrm{km\ s^{-1}}$.
This broadening could be resulted from either Stark (pressure) effect or a
flaring-associated CME at stellar limb. In the context of the CME scenario, the
CME mass is estimated to be $\sim4\times10^{18}$ g and $2\times10^{19}$ g. In
addition, our spectral analysis reveals a temporal variation of the line center
of the narrow H$\alpha$ emission in both events. The variation amplitudes are
at tens of $\mathrm{km\ s^{-1}}$, which could be ascribed to the chromospheric
evaporation in one event, and to a binary scenario in the other one. With the
total flaring energy determined from our photometric monitor, we show a
reinforced trend in which larger the flaring energy, higher the CME mass is.


  We develop a comprehensive implementation of the minimal Left-Right symmetric
model within a FeynRules model file. We derive the complete set of mass spectra
and mixings for the charged and neutral gauge bosons, would-be-Goldstones and
gauge fixing, together with the ghost Lagrangian. In the scalar sector, we
analytically re-derive all the massive states with mixings and devise a
physical input scheme, which expresses the model couplings in terms of masses
and mixing angles of all states. Fermion couplings are determined in closed
form, including the Dirac mixing in the neutrino sector, evaluated explicitly
with the Cayley-Hamilton method. We calculate the one loop next-to-leading QCD
corrections and provide a complete UFO file for NLO studies, demonstrated on
relevant benchmarks. We provide various restricted variants of the model file
with different gauges, massless states, neutrino hierarchies and parity
violating $g_L \neq g_R$ gauge couplings.


  With the help of Kirchberg's and Selberg's theorems, we prove that the
minimal tensor product of $B(H)$ with itself does not have the WEP (weak
expectation property) of Lance.


  In this letter the explicit form of evolution operator of the Tavis-Cummings
model with three and four atoms is given. This is an important progress in
quantum optics or mathematical physics.


  Impressive results in natural language processing (NLP) based on the
Transformer neural network architecture have inspired researchers to explore
viewing offline reinforcement learning (RL) as a generic sequence modeling
problem. Recent works based on this paradigm have achieved state-of-the-art
results in several of the mostly deterministic offline Atari and D4RL
benchmarks. However, because these methods jointly model the states and actions
as a single sequencing problem, they struggle to disentangle the effects of the
policy and world dynamics on the return. Thus, in adversarial or stochastic
environments, these methods lead to overly optimistic behavior that can be
dangerous in safety-critical systems like autonomous driving. In this work, we
propose a method that addresses this optimism bias by explicitly disentangling
the policy and world models, which allows us at test time to search for
policies that are robust to multiple possible futures in the environment. We
demonstrate our method's superior performance on a variety of autonomous
driving tasks in simulation.


  The ordered or chaotic character of orbits of stars moving in the meridional
$(R,z)$ plane of an analytic axisymmetric time-independent disk galaxy model
with an additional spherically symmetric central nucleus is investigated. Our
aim is to determine how the total energy influences the orbital structure of
the galaxy. For this purpose we monitor how the percentage of chaotic orbits as
well as the rates of orbits composing the main regular families evolve as a
function of the value of the energy. In order to distinguish with certainty
between chaotic and ordered motion we use the SALI method in extensive sets of
initial conditions of orbits. Moreover, a spectral method is applied for
identifying the various regular families and also for recognizing the secondary
resonances that bifurcate from them. Our numerical computations suggest that
for low energy levels the observed amount of chaos is high and the orbital
content is rather poor, while for high energy levels, corresponding to global
motion, regular motion dominates and many secondary higher resonances emerge.
We also compared our results with previous related work.


  A symbolic calculus for a pseudo-differential operators acting on sections of
a homogeneous vector bundle over a compact homogeneous space $G/H$ with compact
$G$ and $H$ is developed. We realize the symbol of a pseudo-differential
operator as a linear operator acting on corresponding irreducible unitary
representations of $H$ valued in the algebra $C^\infty(G)$ of smooth functions.
We write down how left invariant vector fields of $SU(2)$ act on the sections
of homogeneous vector bundles associated to the fibration
$\mathbb{T}\hookrightarrow SU(2)\rightarrow\mathbb{C}P^1$, which is known as
the Hopf fibration. Lastly, we outline how functional calculus of a
pseudo-differential operator can be computed using our calculus.


  Despite significant progress in challenging problems across various domains,
applying state-of-the-art deep reinforcement learning (RL) algorithms remains
challenging due to their sensitivity to the choice of hyperparameters. This
sensitivity can partly be attributed to the non-stationarity of the RL problem,
potentially requiring different hyperparameter settings at various stages of
the learning process. Additionally, in the RL setting, hyperparameter
optimization (HPO) requires a large number of environment interactions,
hindering the transfer of the successes in RL to real-world applications. In
this work, we tackle the issues of sample-efficient and dynamic HPO in RL. We
propose a population-based automated RL (AutoRL) framework to meta-optimize
arbitrary off-policy RL algorithms. In this framework, we optimize the
hyperparameters and also the neural architecture while simultaneously training
the agent. By sharing the collected experience across the population, we
substantially increase the sample efficiency of the meta-optimization. We
demonstrate the capabilities of our sample-efficient AutoRL approach in a case
study with the popular TD3 algorithm in the MuJoCo benchmark suite, where we
reduce the number of environment interactions needed for meta-optimization by
up to an order of magnitude compared to population-based training.


  We present the results of complex seismic modelling of the Slowly Pulsating
B-type star HD74560. The star pulsates in five frequencies detected in
photometric observations. For all these frequencies, we identify the mode
degree, $\ell$. For two of them, found also in spectroscopic data, we are able
to derived the empirical values of the complex nonadiabatic parameter $f$. We
test effects of chemical composition and opacity data. Our results show that
the properties of seismic models of SPB stars differ significantly from those
of the more massive $\beta$ Cephei stars.


  A Legendre transform of the recently discovered conformal fixed-point
equation is constructed, providing an unintegrated equation encoding full
conformal invariance within the framework of the effective average action.


  The high-contrast imaging technique is meant to provide insight into those
planets orbiting several astronomical units from their host star. Space
missions such as WFIRST, HabEx, and LUVOIR will measure reflected light spectra
of cold gaseous and rocky planets.
  To interpret these observations we introduce ExoReL$^\Re$ (Exoplanetary
Reflected Light Retrieval), a novel Bayesian retrieval framework to retrieve
cloud properties and atmospheric structures from exoplanetary reflected light
spectra. As a unique feature, it assumes a vertically non-uniform volume mixing
ratio profile of water and ammonia, and use it to construct cloud densities. In
this way, clouds and molecular mixture ratios are consistent.
  We apply ExoReL$^\Re$ on three test cases: two exoplanets ($\upsilon$ And e
and 47 Uma b) and Jupiter. We show that we are able to retrieve the
concentration of methane in the atmosphere, and estimate the position of clouds
when the S/N of the spectrum is higher than 15, in line with previous works.
Moreover, we described the ability of our model of giving a chemical identity
to clouds, and we discussed whether or not we can observe this difference in
the planetary reflection spectrum. Finally, we demonstrate how it could be
possible to retrieve molecular concentrations (water and ammonia in this work)
below the clouds by linking the non-uniform volume mixing ratio profile to the
cloud presence. This will help to constrain the concentration of water and
ammonia unseen in direct measurements.


  We study the properties of the survival probability of an unstable quantum
state described by a Lee Hamiltonian. This theoretical approach resembles
closely Quantum Field Theory (QFT): one can introduce in a rather simple
framework the concept of propagator and Feynman rules, Within this context, we
re-derive (in a detailed and didactical way) the well-known result according to
which the amplitude of the survival probability is the Fourier transform of the
energy distribution (or spectral function) of the unstable state (in turn, the
energy distribution is proportional to the imaginary part of the propagator of
the unstable state). Typically, the survival probability amplitude is the
starting point of many studies of non-exponential decays. This work represents
a further step toward the evaluation of the survival probability amplitude in
genuine relativistic QFT. However, although many similarities exist, QFT
presents some differences w.r.t. the Lee Hamiltonian which should be studied in
the future.


  Using Raman and infrared spectroscopies the spontaneous ferriquadrupolar
ordering has been observed in the rare-earth-based system KDy(MoO$_4$)$_2$.
Ordered quadrupoles in the electron subsystem attend non-equivalent distortions
of rare-earth ions in the ordered phase. The mean field theory explaining the
onset of such a type of ordering has been constructed.


  Motivated by growing applications in two-sided markets, we study a parallel
matching queue with reneging. Demand and supply units arrive to the system and
are matched in an FCFS manner according to a compatibility graph specified by
an N-system. If they cannot be matched upon arrival, they queue and may abandon
the system as time goes by. We derive explicit product forms of the steady
state distributions of this system by identifying a partial balance condition.


  In this letter, we investigate the detailed epidemic spreading process in
scale-free networks with links' weights that denote familiarity between two
individuals and find that spreading velocity reaches a peak quickly then decays
in a power-law form. Numerical study exhibits that the nodes with larger
strength is preferential to be infected, but the hierarchical dynamics are not
clearly found, which is different from the well-known result in unweighed
network case. In addition, also by numerical study, we demonstrate that larger
dispersion of weight of networks results in slower spreading, which indicates
that epidemic spreads more quickly on unweighted scale-free networks than on
weighted scale-free networks with the same condition.


  This paper tackles the problem of semi-supervised video object segmentation,
that is, segmenting an object in a sequence given its mask in the first frame.
One of the main challenges in this scenario is the change of appearance of the
objects of interest. Their semantics, on the other hand, do not vary. This
paper investigates how to take advantage of such invariance via the
introduction of a semantic prior that guides the appearance model.
Specifically, given the segmentation mask of the first frame of a sequence, we
estimate the semantics of the object of interest, and propagate that knowledge
throughout the sequence to improve the results based on an appearance model. We
present Semantically-Guided Video Object Segmentation (SGV), which improves
results over previous state of the art on two different datasets using a
variety of evaluation metrics, while running in half a second per frame.


  In this paper we discuss the reason why the parameters of the Sersic model
best-fitting the major axis light profile of elliptical galaxies can differ
significantly from those derived for the minor axis profile. We show that this
discrepancy is a natural consequence of the fact that the isophote eccentricity
varies with the radius of the isophote and present a mathematical
transformation that allows the minor axis Sersic model to be calculated from
the major axis model, provided that the elliptical isophotes are aligned and
concentric and that their eccentricity can be represented by a well behaved,
though quite general, function of the radius. When there is no variation in
eccentricity only the effective radius changes in the Sersic model, while for
radial-dependent eccentricity the transformation which allows the minor axis
Sersic model to be calculated from the major axis model is given by the Lerch
Phi transcendental function. The proposed transformation was tested using
photometric data for 28 early-type galaxies.


  In the 1930's, nuclear physicists developed the first realistic atomic
models, showing that nuclei were made up of protons and neutrons. In the
1960's, Deep Inelastic Scattering experiments showed that protons and neutrons
had internal structure: quarks and gluons (collectively, partons), and later
experiments showed that the parton momentum distributions are different in
heavy nuclei, compared to those in free nucleons. This difference is not
surprising; partons are sensitive to their environment, and two gluons from
different nucleons may fuse together, for example.
  Understanding how quarks and gluons behave in the nuclear environment is a
significant focus of modern nuclear physics. Recent measurements have provided
us with an improved understanding of how quark and gluon densities are altered
in heavy nuclei. We have also begun to make multi-dimensional pictures of the
nucleus, exploring how these alterations are distributed within heavy nuclei.
We naturally expect these modifications to be largest in the core of a nucleus,
and smaller near its periphery; this can change the effective shape of the
nucleus. We have also started to explore the transverse momentum distribution
of the partons in the nuclei, and, using incoherent photoproduction as a probe,
study event-by-event fluctuations in nucleon and nuclei parton densities.
  This article will explore recent progress in measurements of nuclear
structure at high energy, with some emphasis on these multi-dimensional
pictures. We will also discuss how a future electron-ion collider (EIC) with
high luminosity and center-of-mass energy will make exquisitely detailed images
of partons in a nucleus.


  For any positive integer $n$ we give a ${\mathbb Z}^n$-cork with a ${\mathbb
Z}^n$-effective embedding in a 4-manifold being homeomorphic to $E(n)$. This
means that a cork gives a subset ${\mathbb Z}^n$ in the differential structures
on $E(n)$. Further, we describe handle decompositions of the twisted doubles
(homotopy $S^4$) of Gompf's infinite order corks and show that they are Gluck
twists and log transforms of $S^4$.


  This paper is a guide to the installation and use of the Python package
PYESSENCE. PYESSENCE is designed to evolve linear perturbations to Coupled
Quintessence models with a arbitrary number of cold dark matter (CDM) fluids
and dark energy (DE) scalar fields as dictated by a given model. The equations
are sufficiently general to allow for more exotic dark matter with a non-zero
equation of state. Several example uses are included in order to demonstrate
typical functionality to the potential user. PYESSENCE is released under an
open source modified BSD license and is available on Bitbucket.


  Wikipedia is an online encyclopedia that anyone can edit. In this open model,
some people edits with the intent of harming the integrity of Wikipedia. This
is known as vandalism. We extend the framework presented in (Potthast, Stein,
and Gerling, 2008) for Wikipedia vandalism detection. In this approach, several
vandalism indicating features are extracted from edits in a vandalism corpus
and are fed to a supervised learning algorithm. The best performing classifiers
were LogitBoost and Random Forest. Our classifier, a Random Forest, obtained an
AUC of 0.92236, ranking in the first place of the PAN'10 Wikipedia vandalism
detection task.


  We report proximity effects of spin-orbit coupling in EuO$_{1-x}$ films
capped with a Pt overlayer. Transport measurements suggest that current flows
along a conducting channel at the interface between the Pt and EuO. The
temperature dependence of the resistivity picks up the critical behaviors of
EuO, i.e., the metal-to-insulator transition. We also find an unusual
enhancement of the magnetic anisotropy in this structure from its bulk value
which results from strong spin-orbit coupling across the Pt/EuO interface.


  Majorana fermion dynamics may arise at the edge of Kitaev wires or
superconductors. Alternatively, it can be engineered by using trapped ions or
ultracold atoms in an optical lattice as quantum simulators. This motivates the
theoretical study of Majorana fermions confined to a finite volume, whose
boundary conditions are characterized by self-adjoint extension parameters.
While the boundary conditions for Dirac fermions in $(1+1)$-d are characterized
by a 1-parameter family, $\lambda = - \lambda^*$, of self-adjoint extensions,
for Majorana fermions $\lambda$ is restricted to $\pm i$. Based on this result,
we compute the frequency spectrum of Majorana fermions confined to a 1-d
interval. The boundary conditions for Dirac fermions confined to a 3-d region
of space are characterized by a 4-parameter family of self-adjoint extensions,
which is reduced to two distinct 1-parameter families for Majorana fermions. We
also consider the problems related to the quantum mechanical interpretation of
the Majorana equation as a single-particle equation. Furthermore, the equation
is related to a relativistic Schr\"odinger equation that does not suffer from
these problems.


  A permutation is layered if it contains neither 231 nor 312 as a pattern. It
is known that, if $\sigma$ is a layered permutation, then the density of
$\sigma$ in a permutation of order $n$ is maximized by a layered permutation.
Albert, Atkinson, Handley, Holton and Stromquist [Electron. J. Combin. 9
(2002), R#5] claimed that the density of a layered permutation with layers of
sizes $(a,1,b)$ where $a,b\geq2$ is asymptotically maximized by layered
permutations with a bounded number of layers, and conjectured that the same
holds if a layered permutation has no consecutive layers of size one and its
first and last layers are of size at least two.
  We show that, if $\sigma$ is a layered permutation whose first layer is
sufficiently large and second layer is of size one, then the number of layers
tends to infinity in every sequence of layered permutations asymptotically
maximizing the density of $\sigma$. This disproves the conjecture and the claim
of Albert et al. We complement this result by giving sufficient conditions on a
layered permutation to have asymptotic or exact maximizers with a bounded
number of layers.


  The weak gravity conjecture (WGC) asserts that an Abelian gauge theory
coupled to gravity is inconsistent unless it contains a particle of charge $q$
and mass $m$ such that $q \geq m/m_{\rm Pl}$. This criterion is obeyed by all
known ultraviolet completions and is needed to evade pathologies from stable
black hole remnants. In this paper, we explore the WGC from the perspective of
low-energy effective field theory. Below the charged particle threshold, the
effective action describes a photon and graviton interacting via
higher-dimension operators. We derive infrared consistency conditions on the
parameters of the effective action using i) analyticity of light-by-light
scattering, ii) unitarity of the dynamics of an arbitrary ultraviolet
completion, and iii) absence of superluminality and causality violation in
certain non-trivial backgrounds. For convenience, we begin our analysis in
three spacetime dimensions, where gravity is non-dynamical but has a physical
effect on photon-photon interactions. We then consider four dimensions, where
propagating gravity substantially complicates all of our arguments, but bounds
can still be derived. Operators in the effective action arise from two types of
diagrams: those that involve electromagnetic interactions (parameterized by a
charge-to-mass ratio $q/m$) and those that do not (parameterized by a
coefficient $\gamma$). Infrared consistency implies that $q/m$ is bounded from
below for small $\gamma$.


  In this paper, we develop a symmetric accelerated stochastic Alternating
Direction Method of Multipliers (SAS-ADMM) for solving separable convex
optimization problems with linear constraints. The objective function is the
sum of a possibly nonsmooth convex function and an average function of many
smooth convex functions. Our proposed algorithm combines both ideas of ADMM and
the techniques of accelerated stochastic gradient methods possibly with
variance reduction to solve the smooth subproblem. One main feature of SAS-ADMM
is that its dual variable is symmetrically updated after each update of the
separated primal variable, which would allow a more flexible and larger
convergence region of the dual variable compared with that of standard
deter-ministic or stochastic ADMM. This new stochastic optimization algorithm
is shown to have ergodic converge in expectation with O(1/T) convergence rate,
where T is the number of outer iterations. Our preliminary experiments indicate
the proposed algorithm is very effective for solving separable optimization
problems from big-data applications. Finally, 3-block extensions of the
algorithm and its variant of an accelerated stochastic augmented Lagrangian
method are discussed in the appendix.


  This paper addresses how to improve the computational efficiency and
estimation reliability in cascading outage analysis. We first formulate a
cascading outage as a Markov chain with specific state space and transition
probability by leveraging the Markov property of cascading outages. It provides
a rigorous formulation that allows analytic investigation on cascading outages
in the framework of standard mathematical statistics. Then we derive a
sequential importance sampling (SIS) based simulation strategy for cascading
outage simulation and blackout risk analysis with theoretical justification.
Numerical experiments manifest that the proposed SIS strategy can significantly
bring down the number of simulations and reduce the estimation variance of
cascading outage analysis compared with the traditional Monte Carlo simulation
strategy.


  This paper assesses the hedge effectiveness of an index-based longevity swap
and a longevity cap. Although swaps are a natural instrument for hedging
longevity risk, derivatives with non-linear pay-offs, such as longevity caps,
also provide downside protection. A tractable stochastic mortality model with
age dependent drift and volatility is developed and analytical formulae for
prices of these longevity derivatives are derived. Hedge effectiveness is
considered for a hypothetical life annuity portfolio. The hedging of the life
annuity portfolio is comprehensively assessed for a range of assumptions for
the market price of longevity risk, the term to maturity of the hedging
instruments, as well as the size of the underlying annuity portfolio. The model
is calibrated using Australian mortality data. The results provide a
comprehensive analysis of longevity hedging, highlighting the risk management
benefits and costs of linear and nonlinear payoff structures.


  Evolution of spatially anisotropic perturbation created in the system formed
after Relativistic Heavy Ion Collisions has been studied. The microscopic
evolution of the fluctuations has been examined within the ambit of Boltzmann
Transport Equation (BTE) in a hydrodynamically expanding background. The
expansion of the background composed of Quark Gluon Plasma (QGP) is treated
within the framework of relativistic hydrodynamics. Spatial anisotropic
fluctuations with different geometry have been evolved through Boltzmann
equation. It is observed that the trace of such fluctuation survive the
evolution. Within the relaxation time approximation analytical results have
been obtained for the evolution of these anisotropies. Explicit relations
between fluctuations and transport coefficients have been derived. The mixing
of various Fourier (or $k$) modes of the perturbations during the evolution of
the system has been explicitly demonstrated. This study is very useful in
understanding the presumption that the measured anisotropies in the data from
heavy ion collisions at relativistic energies imitate the initial state
effects. The evolution of correlation function for the perturbation in pressure
has been studied and shown that the initial correlation between two
neighbouring points in real space evolves to a constant value at later time
which gives rise to Dirac delta function for the correlation function in
Fourier space. The power spectrum of the fluctuation in thermodynamic
quantities (like temperature estimated in this work) can be connected to the
fluctuation in transverse momentum of the thermal hadrons measured
experimentally. The bulk viscous coefficient of the QGP has been estimated by
using correlations of pressure fluctuation with the help of Green-Kubo
relation. Angular power spectrum of the anisotropies has been estimated in the
appendix.


  This paper studies the heavy-traffic asymptotics for the multiclass FIFO
M${}^X$/G/1 queue. We first derive the probability generating function of the
joint queue length distribution. Using the probability generating function, we
then present heavy-traffic asymptotic formulas for the joint queue length
distribution and its joint moments (i.e., the joint queue length moments).
These formulas are proved under weaker conditions on the service time
distributions, compared to the ones reported in the literature. This fact leads
us to conjectures that some of the conditions made in the literature are
relaxed.


  I obtain an exact, axially symmetric, stationary solution of Einstein's
equations for two massless spinning particles. The term representing the
spin-spin interaction agrees with recently published approximate work. The
spin-spin force appears to be proportional to the inverse fourth power of the
coordinate distance between the particles.


  The distinctive features of the electronic structure of vortex states in
superconducting graphene are studied within the Bogolubov-de Gennes theory
applied to excitations near the Dirac point. We suggest a scenario describing
the subgap spectrum transformation which occurs with a change in the doping
level. For an arbitrary vorticity and doping level we investigate the problem
of existence of zero energy modes. The crossover to a Caroli - de Gennes -
Matricon type of spectrum is studied.


  In these notes we present a closed-formula solution to the problem of
decomposing traces of Lie algebra generators into symmetrized traces and
structure constants. The solution is written in terms of Solomon idempotents
and exploits a projection derived by Solomon in his work on the
Poincare-Birkhoff-Witt theorem.


  We report a study of the magnetoresistance (MR) of the metallic perovskite
oxide LaNiO$_{3-\delta}$ as a function of the oxygen stoichiometry $\delta$
($\delta \leq$ 0.14), magnetic field (H $\leq 6T$) and temperature (1.5K $\leq
$ T $\leq $ 25K). We find a strong dependence of the nature of MR on the oxygen
stoichiometry. The MR at low temperatures change from positive to negative as
the sample becomes more oxygen deficient (i.e, $\delta$ increases). Some of the
samples which are more resistive, show a resistivity minima at $T_{min}$
$\approx$ 20K. We find that in these samples the MR is positive at T >
$T_{min}$ and negative for T < $T_{min}$. We conclude that in the absence of
strong magnetic interaction, the negative MR in these oxides can arise from
weak localisation effects.


  The context of a software developer is something hard to define and capture,
as it represents a complex network of elements across different dimensions that
are not limited to the work developed on an IDE. We propose the definition of a
software developer context model that takes into account all the dimensions
that characterize the work environment of the developer. We are especially
focused on what the software developer context encompasses at the project level
and how it can be captured. The experimental work done so far show that useful
context information can be extracted from project management tools. The
extraction, analysis and availability of this context information can be used
to enrich the work environment of the developer with additional knowledge to
support her/his work.


  We consider an accretion-disc origin for the broad and luminous
forbidden-line emission observed in ultraluminous X-ray (ULX) sources
CXOJ033831.8-352604 and XMMU 122939.7+075333 in globular clusters hosted by
elliptical galaxies NGC 1399 and NGC 4472, respectively. We will refer to the
latter by the globular cluster name RZ2109. The first has strong [OIII] and
[NII], the second only [OIII]. Both H$\alpha$ and H$\beta$ are very weak or
undetected in both objects. We assume that the large line widths are due to
Keplerian rotation around a compact object and derive expressions for maximum
line luminosities. These idealized models require central masses $\gtrsim100$
and $\gtrsim30000\Msun$ for CXOJ033831.8-352604 and RZ2109, respectively. An
independent, bootstrap argument for the total disc mass yields, for both
systems, $M_{\mathrm{disc}}\gtrsim10^{-4}\Msun$ for a purely metallic disc (and
two orders of magnitude larger for solar metallicities). If Roche-lobe overflow
is implicated, viscous time-scales are $\gtrsim300$ yr. Standard disc theory
then offers another limit on the central masses. Lobe radii for a $\sim1\Msun$
donor are $\gtrsim10^{13}$ cm. We therefore rule out Roche-lobe overflow of a
white dwarf in both systems. Red giants could fill the necessary lobes. Whether
they are too metal-poor to produce the strong forbidden lines without strong
hydrogen emission is unclear.


  The measurement-device-independent (MDI) QKD is considered to be an
alternative to overcome the currently trusted satellite paradigm. However, the
feasibility of the space-based MDI-QKD remains unclear in terms of the factors:
the high-loss uplink between a ground station and a satellite, the limited
duration when two ground stations are simultaneously visible, as well as the
rigorous requirements for the two-photon interference when performing the
Bell-state Measurement (BSM). In this paper, we present a feasibility
assessment of space-based MDI-QKD based on the Micius satellite. Integrated
with the orbital dynamics model and atmosphere channel model, a framework is
presented to explore the whole parameters space including orbit height,
elevation angle, apertures of transceiver and atmospheric turbulence intensity
to give the considerations for improving key rates and subsequently provide a
relevant parameter tradeoff for the implementation of space-based MDI-QKD. We
further investigate the heart of MDI-QKD, the two-photon interference
considerations such as the frequency calibration and time synchronization
technology against Doppler shift, and the way of performing the intensity
optimization method in the dynamic and asymmetric channels. Our work can be
used as a pathfinder to support decisions involving as the selection of the
future quantum communication satellite missions.


  We consider five-dimensional S(2,2|N) Chern-Simons supergravity on M_4 * R .
By fine-tuning the Kaluza-Klein reduction to make the 4d cosmological constant
equal zero, it is shown that selfdual curvatures on M_4 provide exact solutions
to the equations of motion if N=2.


  In composite Higgs models (CHMs), electroweak precision data generically push
colourless composite vector resonances to a regime where they dominantly decay
into pairs of light top partners. This greatly attenuates their traces in
canonical collider searches, tailored for narrow resonances promptly decaying
into Standard Model final states. By reinterpreting the CMS same-sign dilepton
(SS2$\ell$) analysis at the Large Hadron Collider (LHC), originally designed to
search for top partners with electric charge $5/3$, we demonstrate its
significant coverage over this kinematical regime. We also show the reach of
the 13 TeV run of the LHC, with various integrated luminosity options, for a
possible upgrade of the SS2$\ell$ search. The top sector of CHMs is found to be
more fine-tuned in the presence of colourless composite resonances in the few
TeV range.


  We present HST spectra for a sample of six QSOs with intermediate redshift
(z_a < 1) damped Ly-alpha systems. These observations aim at measuring the HI
column density and detect metal lines in order to investigate the metal
enrichment of the gas, as well as the presence of neutral species, molecules
and dust. All systems selected on the basis of 21 cm absorption and/or strong
FeII lines relative to MgII ones turn out to have N(HI) larger than 10^20 cm-2.
It appears that although the scatter of metallicities is as large at z_a<1 as
at high redshift, an increasing proportion of systems with metallicities ~ 30%
solar are found when going at lower redshifts. Our results suggest that
available observations may be biased against dust-rich absorbers. Further, when
all available measurements of N(HI) and [Zn/H] are considered, a clear
deficiency of systems with large N(HI) and high metallicity is apparent. We
conclude that dust extinction causes a preferential selection of QSOs with
intervening gas relatively poor in metals, dust and molecules. As a
consequence, the high end of the HI column density distribution (and hence
Omega_g, the contribution of neutral gas to the cosmological mass density) is
probably more heavily underestimated than previously thought, especially at low
redshift. Such a bias could also explain the high incidence of non-spiral
morphologies in our sample. We stress that observation of a larger sample of
low z damped Ly-alpha systems as well as surveys of damped Ly-alpha systems in
fainter QSOs would give a more representative view of the true diversity of
absorber properties and should help to probe the denser phases of the
interstellar medium in distant galaxies.


  The Sun is a main source of high energy neutrinos. These neutrinos appear as
secondary particles after the Sun absorbs high-energy cosmic rays, that find
there a low-density environment (much thinner than our atmosphere) where most
secondary pions, kaons and muons can decay before they lose energy. The main
uncertainty in a calculation of the solar neutrino flux is due to the effects
of the magnetic fields on the absorption rate of charged cosmic rays. We use
recent data from HAWC on the cosmic-ray shadow of the Sun to estimate this
rate. We evaluate the solar neutrino flux and show that at 1 TeV it is over ten
times larger than the atmospheric one at zenith theta_z=30^o/150^o. The flux
that we obtain has a distinct spectrum and flavor composition, and it could be
detected in current and upcoming neutrino telescopes. KM3NeT, in particular,
looks very promising: it will see the Sun high in the sky (the atmospheric
background is lower there than near the horizon) and expects a very good
angular resolution (the Sun's radius is just 0.27^o).


  We report on refined experimental results concerning the low-temperature
specific heat of the frustrated spin tube material [(CuCl2tachH)3Cl]Cl2. This
substance turns out to be an unusually perfect spin tube system which allows to
study the physics of quasi-one dimensional antiferromagnetic structures in
rather general terms. An analysis of the specific heat data demonstrates that
at low enough temperatures the system exhibits a Tomonaga-Luttinger liquid
behavior corresponding to an effective spin-3/2 antiferromagnetic Heisenberg
chain with short-range exchange interactions. On the other hand, at somewhat
elevated temperatures the composite spin structure of the chain is revealed
through a Schottky-type peak in the specific heat located around 2 K. We argue
that the dominating contribution to the peak originates from gapped magnon-type
excitations related to the internal degrees of freedom of the rung spins.


  Recommender systems help people cope with the problem of information
overload. A recently proposed adaptive news recommender model [Medo et al.,
2009] is based on epidemic-like spreading of news in a social network. By means
of agent-based simulations we study a "good get richer" feature of the model
and determine which attributes are necessary for a user to play a leading role
in the network. We further investigate the filtering efficiency of the model as
well as its robustness against malicious and spamming behaviour. We show that
incorporating user reputation in the recommendation process can substantially
improve the outcome.


  We consider the problem of tabular infinite horizon concave utility
reinforcement learning (CURL) with convex constraints. For this, we propose a
model-based learning algorithm that also achieves zero constraint violations.
Assuming that the concave objective and the convex constraints have a solution
interior to the set of feasible occupation measures, we solve a tighter
optimization problem to ensure that the constraints are never violated despite
the imprecise model knowledge and model stochasticity. We use Bellman
error-based analysis for tabular infinite-horizon setups which allows analyzing
stochastic policies. Combining the Bellman error-based analysis and tighter
optimization equation, for $T$ interactions with the environment, we obtain a
high-probability regret guarantee for objective which grows as
$\Tilde{O}(1/\sqrt{T})$, excluding other factors. The proposed method can be
applied for optimistic algorithms to obtain high-probability regret bounds and
also be used for posterior sampling algorithms to obtain a loose Bayesian
regret bounds but with significant improvement in computational complexity.


  In this paper I introduce the probability distribution of the local overlap
in spin glasses. The properties of the local overlaps are studied in details.
These quantities are related to the recently proposed local version of the
fluctuation dissipation relations: using the general principle of stochastic
stability these local fluctuation dissipation relations can be proved in a way
that is very similar to the usual proof of the fluctuation dissipation
relations for intensive quantities. The local overlap and its probability
distribution play a crucial role in this proof. Similar arguments can be used
to prove that all sites in an aging experiment stay at the same effective
temperature at the same time.


  We give a geometrically exact treatment of percolation through voids around
assemblies of randomly placed impermeable barrier particles, introducing a
computationally inexpensive approach to finding critical barrier density
thresholds marking the transition from bulk permeability to configurations
which do not support fluid or charge transport in the thermodynamic limit. We
implement a dynamic exploration technique which accurately determines the
percolation threshold, which we validate for the case of randomly placed
spheres. We find the threshold densities for randomly oriented hemispherical
fragments and tablets with flat and curved surfaces derived from a sphere
truncated above and below its equator. To incorporate an orientational bias, we
consider barrier particles with dipole moments along the symmetry axis; the
extent of the alignment is then tuned with uniform electric fields of varying
strengths. The latter compete with thermal fluctuations which would eliminate
orientational bias in the absence of an applied field.


  We consider Lane-Emden ground states with polytropic index $0\leq q-1\leq 1$,
that is, minimizers of the Dirichlet integral among $L^q$-normalized functions.
Our main result is a sharp lower bound on the $L^2$-norm of the normal
derivative in terms of the energy, which implies a corresponding isoperimetric
inequality. Our bound holds for arbitrary bounded open Lipschitz sets
$\Omega\subset\mathbb{R}^d$, without assuming convexity.


  This report continues our investigation of effects a simulation design may
have on the conclusions on performance of statistical methods. In the context
of meta-analysis of log-odds-ratios, we consider five generation mechanisms for
control probabilities and log-odds-ratios. Our first report (Kulinskaya et al.
2020) considered constant sample sizes. Here we report on the results for
normally and uniformly distributed sample sizes.


  The braid group $B_{n}$, endowed with Artin's presentation, admits two
distinguished involutions. One is the anti-automorphism ${\rm{rev}}: B_{n} \to
B_{n}$, $v \mapsto \bar{v}$, defined by reading braids in the reverse order
(from right to left instead of left to right). Another one is the conjugation
$\tau:x \mapsto \Delta^{-1}x \Delta$ by the generalized half-twist (Garside
element).
  More generally, the involution ${\rm{rev}}$ is defined for all Artin groups
(equipped with Artin's presentation) and the involution $\tau$ is defined for
all Artin groups of finite type. A palindrome is an element invariant under
rev. We classify palindromes and palindromes invariant under $\tau$ in Artin
groups of finite type. The tools are elementary rewriting and the construction
of explicit left-orderings compatible with rev.
  Finally, we discuss generalizations to Artin groups of infinite type and
Garside groups.


  We propose the Adversarial DEep Learning Transpiler (ADELT), a novel approach
to source-to-source transpilation between deep learning frameworks. ADELT
uniquely decouples code skeleton transpilation and API keyword mapping. For
code skeleton transpilation, it uses few-shot prompting on large language
models (LLMs), while for API keyword mapping, it uses contextual embeddings
from a code-specific BERT. These embeddings are trained in a domain-adversarial
setup to generate a keyword translation dictionary. ADELT is trained on an
unlabeled web-crawled deep learning corpus, without relying on any hand-crafted
rules or parallel data. It outperforms state-of-the-art transpilers, improving
pass@1 rate by 17.4 pts and 15.0 pts for PyTorch-Keras and PyTorch-MXNet
transpilation pairs respectively. We provide open access to our code at
https://github.com/gonglinyuan/adelt.


  By employing a nonlinear quantum kicked rotor model, we investigate the
transport of energy in multidimensional quantum chaos. Parallel numerical
simulations and analytic theory demonstrate that the interplay between
nonlinearity and Anderson localization establishes a perfectly classical
correspondence in the system, neglecting any quantum time reversal. The
resulting dynamics exhibits a nonlinearly-induced, enhanced transport of energy
through soliton wave particles.


  This is the first in a series of papers on geometric mapping theory in Carnot
groups -- and more generally equiregular manifolds -- in which we prove a
number of new structural results for Sobolev (in particular quasisymmetric)
mappings, establishing (partial) rigidity or (partial) regularity theorems,
depending on the context.


  Anycast routing is an area of studies that has been attracting interest of
several researchers in recent years. Most anycast studies conducted in the past
relied on coarse measurement data, mainly due to the lack of infrastructure
where it is possible to test and collect data at same time. In this paper we
present Tangled, an anycast test environment where researchers can run
experiments and better understand the impacts of their proposals on a global
infrastructure connected to the Internet.


  Prior work has uncovered a set of common problems in state-of-the-art
context-based question answering (QA) systems: a lack of attention to the
context when the latter conflicts with a model's parametric knowledge, little
robustness to noise, and a lack of consistency with their answers. However,
most prior work focus on one or two of those problems in isolation, which makes
it difficult to see trends across them. We aim to close this gap, by first
outlining a set of -- previously discussed as well as novel -- desiderata for
QA models. We then survey relevant analysis and methods papers to provide an
overview of the state of the field. The second part of our work presents
experiments where we evaluate 15 QA systems on 5 datasets according to all
desiderata at once. We find many novel trends, including (1) systems that are
less susceptible to noise are not necessarily more consistent with their
answers when given irrelevant context; (2) most systems that are more
susceptible to noise are more likely to correctly answer according to a context
that conflicts with their parametric knowledge; and (3) the combination of
conflicting knowledge and noise can reduce system performance by up to 96%. As
such, our desiderata help increase our understanding of how these models work
and reveal potential avenues for improvements.


  Despite the revolution caused by deep NLP models, they remain black boxes,
necessitating research to understand their decision-making processes. A recent
work by Dalvi et al. (2022) carried out representation analysis through the
lens of clustering latent spaces within pre-trained models (PLMs), but that
approach is limited to small scale due to the high cost of running
Agglomerative hierarchical clustering. This paper studies clustering algorithms
in order to scale the discovery of encoded concepts in PLM representations to
larger datasets and models. We propose metrics for assessing the quality of
discovered latent concepts and use them to compare the studied clustering
algorithms. We found that K-Means-based concept discovery significantly
enhances efficiency while maintaining the quality of the obtained concepts.
Furthermore, we demonstrate the practicality of this newfound efficiency by
scaling latent concept discovery to LLMs and phrasal concepts.


  The use of artificial immune systems in intrusion detection is an appealing
concept for two reasons. Firstly, the human immune system provides the human
body with a high level of protection from invading pathogens, in a robust,
self-organised and distributed manner. Secondly, current techniques used in
computer security are not able to cope with the dynamic and increasingly
complex nature of computer systems and their security. It is hoped that
biologically inspired approaches in this area, including the use of
immune-based systems will be able to meet this challenge. Here we review the
algorithms used, the development of the systems and the outcome of their
implementation. We provide an introduction and analysis of the key developments
within this field, in addition to making suggestions for future research.


  This paper studies models in which hypothesis tests have trivial power, that
is, power smaller than size. This testing impossibility, or impossibility type
A, arises when any alternative is not distinguishable from the null. We also
study settings in which it is impossible to have almost surely bounded
confidence sets for a parameter of interest. This second type of impossibility
(type B) occurs under a condition weaker than the condition for type A
impossibility: the parameter of interest must be nearly unidentified. Our
theoretical framework connects many existing publications on impossible
inference that rely on different notions of topologies to show models are not
distinguishable or nearly unidentified. We also derive both types of
impossibility using the weak topology induced by convergence in distribution.
Impossibility in the weak topology is often easier to prove, it is applicable
for many widely-used tests, and it is useful for robust hypothesis testing. We
conclude by demonstrating impossible inference in multiple economic
applications of models with discontinuity and time-series models.


  We investigate the low-energy properties of a generalized quantum sine-Gordon
model in one dimension with a self-dual symmetry. This model describes a class
of quantum phase transitions that stems from the competition of different
orders. This SU(N) self-dual sine-Gordon model is shown to be equivalent to an
SO(N)_2 conformal field theory perturbed by a current-current interaction,
which is related to an integrable fermionic model introduced by Andrei and
Destri. In the context of spin-chain problems, we give several realizations of
this self-dual sine-Gordon model and discuss the universality class of the
transitions.


  A general mathematical derivation is given of the uncertainty arising from
photon statistics in spectroscopic determination of line shift and width, in
the presence of a background spectrum.


  We propose second-order topological insulators (SOTIs) whose lattice
structure has the hexagonal symmetry $C_{6}$ in three and two dimensions. We
start with a three-dimensional weak topological insulator constructed on the
stacked triangular lattice, which has only side topological surface states. We
then introduce an additional mass term which gaps out the side surface states
but preserves the hinge states. The resultant system is a three-dimensional
SOTI. The bulk topological quantum number is shown to be the $\mathbb{Z}_{3}$
index protected by the inversion time-reversal symmetry $IT$ and the
rotoinversion symmetry $C_{6}I$. We obtain three phases; trivial, strong and
weak SOTI phases. We argue the origin of these two types of SOTIs. A hexagonal
prism is a typical structure respecting these symmetries, where six topological
hinge states emerge at the side. The building block is a hexagon in two
dimensions, where topological corner states emerge at the six corners in the
SOTI phase. Strong and weak SOTIs are obtained when the interlayer hopping
interaction is strong and weak, respectively. They are characterized by the
emergence of hinge states attached to or detached from the bulk bands.


  Let $A$ be an $n$ by $n$ matrix with numerical range $W(A) := \{ q^{*}Aq : q
\in \mathbb{C}^n , ~\| q \|_2 = 1 \}$. We are interested in functions $\hat{f}$
that maximize $\| f(A) \|_2$ (the matrix norm induced by the vector 2-norm)
over all functions $f$ that are analytic in the interior of $W(A)$ and
continuous on the boundary and satisfy $\max_{z \in W(A)} | f(z) | \leq 1$. It
is known that there are functions $\hat{f}$ that achieve this maximum and that
such functions are of the form $B\circ\phi$, where $\phi$ is any conformal
mapping from the interior of $W(A)$ to the unit disk $\mathbb{D}$, extended to
be continuous on the boundary of $W(A)$, and $B$ is a Blaschke product of
degree at most $n-1$. It is not known if a function $\hat{f}$ that achieves
this maximum is unique, up to multiplication by a scalar of modulus one. We
show that this is the case when $A$ is a $2\times 2$ nonnormal matrix or a
Jordan block, but we give examples of some $3\times 3$ matrices with elliptic
numerical range for which two different functions $\hat{f}$, involving the same
conformal mapping but Blaschke products of different degrees, achieve the same
maximal value of $||f(A)||_2$.


  Hydrodynamics can be formulated in terms of a perturbative series in
derivatives of the temperature, chemical potential, and flow velocity around an
equilibrium state. Different formulations for this series have been proposed
over the years, which consequently led to the development of various
hydrodynamic theories. In this work, we discuss the relativistic
generalizations of the perturbative expansions put forward by Chapman and
Enskog, and Hilbert, using general matching conditions in kinetic theory. This
allows us to describe, in a comprehensive way, how different out-of-equilibrium
definitions for the hydrodynamic fields affect the development of the
hydrodynamic perturbative series. We provide a perturbative method for
systematically deriving the hydrodynamic formulation recently proposed by
Bemfica, Disconzi, Noronha, and Kovtun (BDNK) from relativistic kinetic theory.
The various transport coefficients that appear in BDNK (at first-order) are
explicitly computed using a new formulation of the relaxation time
approximation for the Boltzmann equation. Assuming Bjorken flow, we also
determine the hydrodynamic attractors of BDNK theory and compare the overall
hydrodynamic evolution obtained using this formulation with that generated by
the Israel-Stewart equations of motion and also kinetic theory.


  It is pointed out that the meson cloud model predicts a substantial
polarization of the sea quarks of the nucleon due to interference of $\pi$ and
$\rho$ exchanges. This polarization is strongly flavour dependent. The model
gives an explanation of a strong increase in the structure function $g_1$ with
isospin I=1 at small $x$.


  We consider the linearised graviton in $4d$ Minkowski space and decompose it
into tensor spherical harmonics and fix the gauge. The Gauss law of gravity
implies that certain radial components of the Riemann tensor of the graviton on
the sphere label the superselection sectors for the graviton. We show that
among these 6 normal components of the Riemann tensor, 2 are related locally to
the algebra of gauge-invariant operators in the sphere. From the two-point
function of these components of the Riemann tensor on $S^2$ we compute the
logarithmic coefficient of the entanglement entropy of these superselection
sectors across a spherical entangling surface. For sectors labelled by each of
the two components of the Riemann tensor these coefficients are equal and their
total contribution is given by $-\frac{16}{3}$. We observe that this
coefficient coincides with that extracted from the edge partition function of
the massless spin-2 field on the 4-sphere when written in terms of its
Harish-Chandra character. As a preliminary step, we also evaluate the
logarithmic coefficient of the entanglement entropy from the superselection
sectors labelled by the radial component of the electric field of the $U(1)$
theory in even $d$ dimensions. We show that this agrees with the corresponding
coefficient of the edge Harish-Chandra character of the massless spin-1 field
on $S^d$.


  The consequences of dynamical screening of Coulomb interaction among
correlated electrons in realistic materials have not been widely considered
before. In this letter we try to incorporate a frequency dependent Coulomb
interaction into the state-of-the-art ab initio electronic structure computing
framework of local density approximation plus dynamical mean-field theory, and
then choose SrVO3 as a prototype material to demonstrate the importance of
dynamical screening effect. It is shown to renormalise the spectral weight near
the Fermi level, to increase the effective mass, and to suppress the t2g
quasiparticle band width apparently. The calculated results are in accordance
with very recent angle-resolved photoemission spectroscopy experiments and Bose
factor ansatz calculations.


  This paper introduces a novel framework for generative models based on
Restricted Kernel Machines (RKMs) with joint multi-view generation and
uncorrelated feature learning, called Gen-RKM. To enable joint multi-view
generation, this mechanism uses a shared representation of data from various
views. Furthermore, the model has a primal and dual formulation to incorporate
both kernel-based and (deep convolutional) neural network based models within
the same setting. When using neural networks as explicit feature-maps, a novel
training procedure is proposed, which jointly learns the features and shared
subspace representation. The latent variables are given by the
eigen-decomposition of the kernel matrix, where the mutual orthogonality of
eigenvectors represents the learned uncorrelated features. Experiments
demonstrate the potential of the framework through qualitative and quantitative
evaluation of generated samples on various standard datasets.


  A viable approach towards Quantum Gravity is the Doubly Special Relativity
(DSR) framework in which an observer-independent finite energy upper bound (or
a finite smallest length scale) appears quite naturally. In this work, we have
studied the thermodynamic properties of an ideal gas in a specific DSR
framework, known as the Magueijo-Smolin (MS) Model. We use the fact that DSR
can be considered as nonlinear representation of Lorentz Group. Subsequently,
various thermodynamic parameters of ideal gas have been derived in this
modified framework to compare the corresponding deviations from the usual
scenario due to the presence of the invariant energy (length) scale.


  Cathodoluminescence spectra employing a shadow mask technique of InGaN layers
grown by metal organic chemical vapor deposition on Si(111) substrates are
reported. Sharp lines originating from InGaN quantum dots are observed.
Temperature dependent measurements reveal thermally induced carrier
redistribution between the quantum dots. Spectral diffusion is observed and was
used as a tool to correlate up to three lines that originate from the same
quantum dot. Variation of excitation density leads to identification of exciton
and biexciton. Binding and anti-binding complexes are discovered.


  Chandra is detecting a significant population of normal and starburst
galaxies in extremely deep X-ray exposures. For example, approximately 15% of
the sources arising in the 2 Ms Chandra Deep Field-North survey are fairly
normal galaxies, where "normal" means "Milky Way-type" X-ray emission rather
than simply exhibiting an "optically normal" spectrum. Many of these galaxies
are being detected at large look-back times z=0.1-0.5, allowing the study of
the evolution of X-ray binary populations over significant cosmological
timescales. We are also detecting individual off-nuclear ultraluminous X-ray
sources (e.g., X-ray binaries), providing the first direct constraints on the
prevalence of lower-mass black holes at significantly earlier times. The X-ray
emission from such "normal" galaxies may also be a useful star-formation rate
indicator, based on radio/X-ray cross-identifications. We describe the
contribution of normal galaxies to the populations which make up the X-ray
background and present their directly measured X-ray number counts. We find
that normal and starburst galaxies should dominate the 0.5--2 keV number counts
at X-ray fluxes fainter than 7e-18 erg cm^{-2} s^{-1} (thus they will outnumber
the "mighty" AGN). Finally, we look to the future, suggesting that it is
important that the population of X-ray faint normal and starburst galaxies be
well constrained in order to design the next generation of X-ray observatories.