  A simplification strategy for Segmented Mirror Splitters (SMS) used as beam
combiners is presented. These devices are useful for compact beam division and
combination of linear and 2-D arrays. However, the standard design requires
unique thin-film coating sections for each input beam and thus potential for
scaling to high beam-counts is limited due to manufacturing complexity. Taking
advantage of the relative insensitivity of the beam combination process to
amplitude variations, numerical techniques are used to optimize
highly-simplified designs with only one, two or three unique coatings. It is
demonstrated that with correctly chosen coating reflectivities, the simplified
optics are capable of high combination efficiency for several tens of beams.
The performance of these optics as beamsplitters in multicore fiber amplifier
systems is analyzed, and inhomogeneous power distribution of the simplified
designs is noted as a potential source of combining loss in such systems. These
simplified designs may facilitate further scaling of filled-aperture coherently
combined systems.


  We revisit the high energy semi-classical description of the exclusive
processes DVCS, TCS, and Double DVCS by explicitly keeping track of the Feynman
$x$ dependence in both the hard and the hadronic matrix elements. This is
achieved by a modification of the standard shock wave approximation to derive
the effective Feynman rules, which leads to a generic expression on which we
then perform a partial twist expansion to get rid of quantities suppressed by
the proper physical scales. We obtain a compact factorized master formula that
can be used to investigate the Bjorken limit at leading twist. In particular,
we recover the full one-loop result in the collinear limit for pure gluon
exchange with the target. Finally, we discuss the subtleties in taking the
simultaneous collinear and small $x$ limit.


  Pre-trained contextual representations have led to dramatic performance
improvements on a range of downstream tasks. Such performance improvements have
motivated researchers to quantify and understand the linguistic information
encoded in these representations. In general, researchers quantify the amount
of linguistic information through probing, an endeavor which consists of
training a supervised model to predict a linguistic property directly from the
contextual representations. Unfortunately, this definition of probing has been
subject to extensive criticism in the literature, and has been observed to lead
to paradoxical and counter-intuitive results. In the theoretical portion of
this paper, we take the position that the goal of probing ought to be measuring
the amount of inductive bias that the representations encode on a specific
task. We further describe a Bayesian framework that operationalizes this goal
and allows us to quantify the representations' inductive bias. In the empirical
portion of the paper, we apply our framework to a variety of NLP tasks. Our
results suggest that our proposed framework alleviates many previous problems
found in probing. Moreover, we are able to offer concrete evidence that -- for
some tasks -- fastText can offer a better inductive bias than BERT.


  It is proposed a new method of compressing laser pulse by fast extending
plasma gratings(FEPG), which is created by ionizing the hypersound wave
generated by stimulated Brillouin scattering(SBS) in the background gas.
Ionized by a short laser pulse, the phonon forms a light-velocity FEPG to fully
reflect a resonant pump laser. As the reflecting surface moves with a light
velocity, the reflected pulse is temporally overlapped and compressed. This
regime is supported by the simulation results of a fully kinetic
particle-in-cell(PIC) code Opic with a laser wavelength of 1um, displaying a
pump pulse is compressed from 13ps to a few cycles(7.2fs), with an efficiency
close to 80%. It is a promising method to produce critical laser powers due to
several features: high efficiency without a linear stage, robustness to plasma
instabilities, no seed and a wide range of pump intensity.


  The Unfriendly Partition Conjecture posits that every countable graph admits
a 2-colouring in which for each vertex there are at least as many bichromatic
edges containing that vertex as monochromatic ones. This is not known in
general, but it is known that a 3-colouring with this property always exists.
Anholcer, Bosek and Grytczuk recently gave a list-colouring version of this
conjecture, and proved that such a colouring exists for lists of size 4. We
improve their result to lists of size 3; the proof extends to directed acyclic
graphs. We also discuss some generalisations.


  Radiogenomics is an emerging field in cancer research that combines medical
imaging data with genomic data to predict patients clinical outcomes. In this
paper, we propose a multivariate sparse group lasso joint model to integrate
imaging and genomic data for building prediction models. Specifically, we
jointly consider two models, one regresses imaging features on genomic
features, and the other regresses patients clinical outcomes on genomic
features. The regularization penalties through sparse group lasso allow
incorporation of intrinsic group information, e.g. biological pathway and
imaging category, to select both important intrinsic groups and important
features within a group. To integrate information from the two models, in each
model, we introduce a weight in the penalty term of each individual genomic
feature, where the weight is inversely correlated with the model coefficient of
that feature in the other model. This weight allows a feature to have a higher
chance of selection by one model if it is selected by the other model. Our
model is applicable to both continuous and time to event outcomes. It also
allows the use of two separate datasets to fit the two models, addressing a
practical challenge that many genomic datasets do not have imaging data
available. Simulations and real data analyses demonstrate that our method
outperforms existing methods in the literature.


  Titanate nanotubes (TNT) with different sodium contents have been synthesised
using a hydrothermal approach and a swift and highly controllable post-washing
processes. The influence of the sodium/proton replacement on the structural and
morphological characteristics of the prepared materials was analysed. Different
optical behaviour was observed depending on the Na+/H+ samples' content. A band
gap energy of 3.27\pm0.03 eV was estimated for the material with higher sodium
content while a value of 2.81\pm0.02 eV was inferred for the most protonated
material, which therefore exhibits an absorption edge in the near visible
region. The point of zero charge of the materials was determined and the
influence of the sodium content on the adsorption of both cationic and anionic
organic dyes was studied. The photocatalytic performance of the TNT samples was
evaluated in the rhodamine 6G degradation process. Best photodegradation
results were obtained when using the most protonated material as catalyst,
although this material has shown the lowest R6G adsorption capability.


  Since the introduction of massive MIMO (mMIMO), the design of a transceiver
with feasible complexity has been a challenging problem. Initially, it was
believed that the main issue in this respect is the overall RF-cost. However,
as mMIMO is becoming more and more a key technology for future wireless
networks, it is realized, that the RF-cost is only one of many implementational
challenges and design trade-offs. In this paper, we present, analyze and
compare various novel mMIMO architectures, considering recent emerging
technologies such as intelligent surface-assisted and Rotman lens based
architectures. These are compared to the conventional fully digital (FD) and
hybrid analog-digital beamforming (HADB) approaches. To enable a fair
comparison, we account for various hardware imperfections and losses and
utilize a novel, universal algorithm for signal precoding. Based on our
thorough investigations, we draw a generic efficiency to quality trade-off for
various mMIMO architectures. We find that in a typical cellular communication
setting the reflect/transmit array based architectures sketch the best overall
trade-off. Further, we show that in a qualitative ranking the power efficiency
of the considered architectures is independent of the frequency range.


  We propose a unifying theoretical framework for the analysis of first-passage
time distributions in two important classes of stochastic processes in which
the diffusivity of a particle evolves randomly in time. In the first class of
"diffusing diffusivity" models, the diffusivity changes continuously via a
prescribed stochastic equation. In turn, the diffusivity switches randomly
between discrete values in the second class of "switching diffusion" models.
For both cases, we quantify the impact of the diffusivity dynamics onto the
first-passage time distribution of a particle via the moment-generating
function of the integrated diffusivity. We provide general formulas and some
explicit solutions for some particular cases of practical interest.


  This is some lecture notes I wrote for the masterclass \emph{Rigidity of
$C^*$-algebras associated to dynamics} held at the University of Copenhagen
October 16-20, 2017.
  The notes is attempt to give an introduction to how \'etale groupoids can be
used to obtain $C^*$-rigidity result for topological dynamical systems.


  The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS)
searches for the neutrinoless double beta decay of 76-Ge. In view of the GERDA
Phase II data collection, four new 228-Th radioactive sources for the
calibration of the germanium detectors enriched in 76-Ge have been produced
with a new technique, leading to a reduced neutron flux from ( alpha; n )
reactions. The gamma activities of the sources were determined with a total
uncertainty of 4 percent using an ultra-low background HPGe detector operated
underground at LNGS. The emitted neutron flux was determined using a low
background LiI(Eu) detector and a 3-He counter at LNGS. In both cases, a
reduction of about one order of magnitude with respect to commercially
available 228-Th sources was obtained. Additionally, a specific leak test with
a sensitivity to leaks down to 10 mBq was developed to investigate the
tightness of the stainless steel capsules housing the sources after their use
in cryogenic environment.


  One of the noise sources that currently limits gravitational wave (GW)
detectors comes from the quantum nature of the light causing uncertain
amplitude and phase. Phase uncertainty limits the precision of an
interferometric measurement. This measurement is also subject to quantum
back-action, caused by the radiation pressure force fluctuations produced by
the amplitude uncertainty (QRPN). In order to lower this quantum noise, GW
detectors plan to use squeezed light injection. In this thesis, I focus on
using radiation-pressure-mediated optomechanical (OM) interaction to generate
squeezed light. Creating squeezed states by using OM interaction enables
wavelength-independent squeezed light sources that may also be more compact and
robust than traditionally used non-linear crystals. We analyze the system with
realistic imperfections (losses & classical noise), and use the concepts to
design an experiment to obtain the most possible squeezing in a broad
audio-frequency band at room temperature. This involves an optimization for the
optical properties of the cavity and the mechanical properties of the
oscillator. We then show its experimental implementation, and subsequent
observation of QRPN as well as OM squeezing. These are the first ever direct
observations of a room temperature oscillator's motion being overwhelmed by
vacuum fluctuations. This is shown in the low frequency band, which is relevant
to GW detectors, but poses its own technical challenges, and hence has not been
done before. Being in the back-action dominated regime along with optimized
optical properties has also enabled us to observe OM squeezing. That is the
first direct observation of quantum noise suppression in a room temperature OM
system. It is also the first direct evidence of quantum correlations in the
audio frequency band, in a broad band at non-resonant frequencies.


  Vertebral fracture grading classifies the severity of vertebral fractures,
which is a challenging task in medical imaging and has recently attracted Deep
Learning (DL) models. Only a few works attempted to make such models
human-interpretable despite the need for transparency and trustworthiness in
critical use cases like DL-assisted medical diagnosis. Moreover, such models
either rely on post-hoc methods or additional annotations. In this work, we
propose a novel interpretable-by-design method, ProtoVerse, to find relevant
sub-parts of vertebral fractures (prototypes) that reliably explain the model's
decision in a human-understandable way. Specifically, we introduce a novel
diversity-promoting loss to mitigate prototype repetitions in small datasets
with intricate semantics. We have experimented with the VerSe'19 dataset and
outperformed the existing prototype-based method. Further, our model provides
superior interpretability against the post-hoc method. Importantly, expert
radiologists validated the visual interpretability of our results, showing
clinical applicability.


  The vibrational properties (phonons) of a one-dimensional periodic phase of
atoms physisorbed in the external groove of the carbon nanotube bundle are
studied. Analytical expressions for the phonon dispersion relations are
derived. The derived expressions are applied to Xe, Kr and Ar adsorbates. The
specific heat pertaining to dense phases of these adsorbates is calculated.


  Anomaly detection in medical imaging is to distinguish the relevant
biomarkers of diseases from those of normal tissues. Deep supervised learning
methods have shown potentials in various detection tasks, but its performances
would be limited in medical imaging fields where collecting annotated anomaly
data is limited and labor-intensive. Therefore, unsupervised anomaly detection
can be an effective tool for clinical practices, which uses only unlabeled
normal images as training data. In this paper, we developed an unsupervised
learning framework for pixel-wise anomaly detection in multi-contrast magnetic
resonance imaging (MRI). The framework has two steps of feature generation and
density estimation with Gaussian mixture model (GMM). A feature is derived
through the learning of contrast-to-contrast translation that effectively
captures the normal tissue characteristics in multi-contrast MRI. The feature
is collaboratively used with another feature that is the low-dimensional
representation of multi-contrast images. In density estimation using GMM, a
simple but efficient way is introduced to handle the singularity problem which
interrupts the joint learning process. The proposed method outperforms previous
anomaly detection approaches. Quantitative and qualitative analyses demonstrate
the effectiveness of the proposed method in anomaly detection for
multi-contrast MRI.


  It is shown that the Schwarzschild-de Sitter (SdS) spacetime has the
fundamental temperature. This temperature describes the thermal processes of
decay of the composite particles and the other processes, which are
energetically forbidden in the Minkowski spacetime, but are allowed in the de
Sitter and in SdS backgrounds. In particular, this temperature describes the
probability of ionization of the atom in the SdS, which is observed by the
stationary observer at the point where the shift function (velocity) in the
Arnowitt-Deser-Misner formalism changes sign. This activation temperature does
not depend on the black hole mass and is fully determined by the Hubble
parameter, $T_{\rm SdS}=\sqrt{3}H/\pi$. This temperature is twice the
Bousso-Hawking temperature $T_{\rm BH}$, which characterizes the limit of
degenerate Lorentzian Schwarzschild-de Sitter universe, when the cosmological
and black hole horizons are close to each other, $T_{\rm SdS}=2T_{\rm BH}$.
  The similar doubling of the temperature of Hawking radiation is known in the
pure de Sitter spacetime, where the corresponding local temperature describing
the ionization of atoms is twice the Gibbons-Hawking temperature, $T_{\rm
dS}=2T_{\rm GH}=H/\pi$. We suggest that the activation temperature $T_{\rm dS}$
can be considered as the thermodynamic temperature of the de Sitter state,
which determines the local entropy in this state, $s=3H/4G$.


  We compute the thermal conductivity and sound attenuation length of a dilute
atomic Fermi gas in the framework of kinetic theory. Above the critical
temperature for superfluidity, T_c, the quasi-particles are fermions, whereas
below T_c, the dominant excitations are phonons. We calculate the thermal
conductivity in both cases. We find that at unitarity the thermal conductivity
\kappa in the normal phase scales as \kappa ~ T^{3/2}. In the superfluid phase
we find \kappa ~ T^{2}. At high temperature the Prandtl number, the ratio of
the momentum and thermal diffusion constants, is 2/3. The ratio increases as
the temperature is lowered. As a consequence we expect sound attenuation in the
normal phase just above T_c to be dominated by shear viscosity. We comment on
the possibility of extracting the shear viscosity of the dilute Fermi gas at
unitarity using measurements of the sound absorption length.


  Spinodal decomposition in a near-critical binary fluid is examined for
experimental scenarios in which the liquid is quenched abruptly by changing the
pressure and the subsequent phase separation occurs with no heat flow from the
outside, i.e., adiabatically. Equations of motion for the system volume and
effective temperature are derived. It is shown that for this case that the
nonequilibrium decomposition process is well approximated as one of constant
entropy, i.e., as thermodynamically reversible. Quantitative comparison, with
no adjustable parameters, is made with experimental light scattering data of
Bailey and Cannell [$\rm {Phys.\ Rev.\ Lett.\ }{\bf 70}$, 2110 (1993)]. It is
found that including these adiabatic effects accounts for most of the
discrepancies between these experiments and previous isothermal theory. The
equilibrium static critical properties of the isothermal theory are also
examined, this discussion serving to justify some approximations in the current
theory.


  We study the gravitational-wave signal stemming from strongly coupled models
featuring both, dark chiral and confinement phase transitions. We therefore
identify strongly coupled theories that can feature a first-order phase
transition. Employing the Polyakov-Nambu-Jona-Lasinio model, we focus our
attention on SU(3) Yang-Mills theories featuring fermions in fundamental,
adjoint, and two-index symmetric representations. We discover that for the
gravitational-wave signals analysis, there are significant differences between
the various representations. Interestingly we also observe that the two-index
symmetric representation leads to the strongest first-order phase transition
and therefore to a higher chance of being detected by the Big Bang Observer
experiment. Our study of the confinement and chiral phase transitions is
further applicable to extensions of the Standard Model featuring composite
dynamics.


  Freeze-out of the gas phase elements onto cold grains in dense interstellar
and circumstellar media builds up ice mantles consisting of molecules that are
mostly formed in situ (H2O, NH3, CO2, CO, CH3OH, and more). This review
summarizes the detected infrared spectroscopic ice features and compares the
abundances across Galactic, extragalactic, and solar system environments. A
tremendous amount of information is contained in the ice band profiles.
Laboratory experiments play a critical role in the analysis of the
observations. Strong evidence is found for distinct ice formation stages,
separated by CO freeze out at high densities. The ice bands have proven to be
excellent probes of the thermal history of their environment. The evidence for
the long-held idea that processing of ices by energetic photons and cosmic rays
produces complex molecules is weak. Recent state of the art observations show
promise for much progress in this area with planned infrared facilities.


  Non-relativistic quantum chromodynamics (NRQCD) factorization formulism is an
important approach to investigate the production of the heavy quarkonium. In
this paper, we study the production of the $\Omega_{ccc}$ and $\Omega_{bbb}$ at
the $e^+e^-$ collider, using the NRQCD factorization formulism. We calculate
the total and differential cross sections exactly of the processes,
$e^+e^-\rightarrow \gamma^*/Z^*\rightarrow \Omega_{ccc}\bar{c}\bar{c}\bar{c}$
and $e^+e^-\rightarrow \gamma^*/Z^*\rightarrow
\Omega_{bbb}\bar{b}\bar{b}\bar{b}$, in the leading order at the $e^+e^-$
colliders with different energies. The results show that it is hard to observe
them at the $e^+e^-$ collider directly.


  Cloud computing has radically changed the way organisations operate their
software by allowing them to achieve high availability of services at
affordable cost. Containerized microservices is an enabling technology for this
change, and advanced container orchestration platforms such as Kubernetes are
used for service management. Despite the flourishing ecosystem of monitoring
tools for such orchestration platforms, service management is still mainly a
manual effort.
  The modeling of cloud computing systems is an essential step towards
automatic management, but the modeling of cloud systems of such complexity
remains challenging and, as yet, unaddressed. In fact modeling resource
consumption will be a key to comparing the outcome of possible deployment
scenarios. This paper considers how to derive resource models for cloud systems
empirically. We do so based on models of deployed services in a formal modeling
language with explicit CPU and memory resources; once the adherence to the real
system is good enough, formal properties can be verified in the model.
  Targeting a likely microservices application, we present a model of
Kubernetes developed in Real-Time ABS. We report on leveraging data collected
empirically from small deployments to simulate the execution of higher
intensity scenarios on larger deployments. We discuss the challenges and
limitations that arise from this approach, and identify constraints under which
we obtain satisfactory accuracy.


  We present here some studies on noise-induced order and synchronous firing in
a system of bidirectionally coupled generic type-I neurons. We find that
transitions from unsynchronized to completely synchronized states occur beyond
a critical value of noise strength that has a clear functional dependence on
neuronal coupling strength and input values. For an inhibitory-excitatory (IE)
synaptic coupling, the approach to a partially synchronized state is shown to
vary qualitatively depending on whether the input is less or more than a
critical value. We find that introduction of noise can cause a delay in the
bifurcation of the firing pattern of the excitatory neuron for IE coupling.


  For general varifolds in Euclidean space, we prove an isoperimetric
inequality, adapt the basic theory of generalised weakly differentiable
functions, and obtain several Sobolev type inequalities. We thereby intend to
facilitate the use of varifold theory in the study of diffused surfaces.


  We determine the energy of an interface between a multiband superconducting
and a normal half-space, in presence of an applied magnetic field, based on a
multiband Ginzburg-Landau (GL) approach. We obtain that the multiband surface
energy is fully determined by the critical temperature, electronic densities of
states, and superconducting gap functions associated with the different band
condensates. This furthermore yields an expression for the thermodynamic
critical magnetic field, in presence of an arbitrary number of contributing
bands. Subsequently, we investigate the sign of the surface energy as a
function of material parameters, through numerical solution of the GL
equations. Here, we consider two distinct cases: (i) standard multiband
superconductors with attractive interactions, and (ii) a three-band
superconductor with a chiral ground state with phase frustration, arising from
repulsive interband interactions. Furthermore, we apply this approach to
several prime examples of multiband superconductors, such as metallic hydrogen
and MgB$_2$, based on microscopic parameters obtained from first-principles
calculations.


  Sunspots, which harbor both magnetic polarities within one penumbra, are
called delta-spots. They are often associated with flares. Nevertheless, there
are only very few detailed observations of the spatially resolved magnetic
field configuration. We present an investigation performed with the Tenerife
Infrared Polarimeter at the Vacuum Tower Telescope in Tenerife. We observed a
sunspot with a main umbra and several additional umbral cores, one of them with
opposite magnetic polarity (the delta-umbra). The delta-spot is divided into
two parts by a line along which central emissions of the spectral line Ca II
854.2 nm appear. The Evershed flow comming from the main umbra ends at this
line. In deep photospheric layers, we find an almost vertical magnetic field
for the delta-umbra, and the magnetic field decreases rapidly with height,
faster than in the main umbra. The horizontal magnetic field in the direction
connecting main and delta-umbra is rather smooth, but in one location next to a
bright penumbral feature at some distance to the delta-umbra, we encounter a
change of the magnetic azimuth by 90 degrees from one pixel to the next. Near
the delta-umbra, but just outside, we encounter a blue-shift of the spectral
line profiles which we interpret as Evershed flow away from the delta-umbra.
Significant electric current densities are observed at the dividing line of the
spot and inside the delta-umbra.


  The paper addresses the two-point correlations of electromagnetic waves in
general random, bi-anisotropic media whose constitutive tensors are complex
Hermitian, positive- or negative-definite matrices. A simplified version of the
two-frequency Wigner distribution (2f-WD) for polarized waves is introduced and
the closed form Wigner-Moyal equation is derived from the Maxwell equations. In
the weak-disorder regime with an arbitrarily varying background the
two-frequency radiative transfer (2f-RT) equations for the associated $2\times
2$ coherence matrices are derived from the Wigner-Moyal equation by using the
multiple scale expansion. In birefringent media, the coherence matrix becomes a
scalar and the 2f-RT equations take the scalar form due to the absence of
depolarization. A paraxial approximation is developed for spatialy anisotropic
media. Examples of isotropic, chiral, uniaxial and gyrotropic media are
discussed.


  This is a short and simple introduction into perturbiners, that is, the
solutions of field equations which are generating functions for tree
amplitudes. The perturbiners have been constructed in Yang-Mills, in SUSY
Yang-Mills, in gravity, and in sin(h)-Gordon.


  Aspect-based sentiment analysis (ABSA) aims to predict the sentiment towards
a specific aspect in the text. However, existing ABSA test sets cannot be used
to probe whether a model can distinguish the sentiment of the target aspect
from the non-target aspects. To solve this problem, we develop a simple but
effective approach to enrich ABSA test sets. Specifically, we generate new
examples to disentangle the confounding sentiments of the non-target aspects
from the target aspect's sentiment. Based on the SemEval 2014 dataset, we
construct the Aspect Robustness Test Set (ARTS) as a comprehensive probe of the
aspect robustness of ABSA models. Over 92% data of ARTS show high fluency and
desired sentiment on all aspects by human evaluation. Using ARTS, we analyze
the robustness of nine ABSA models, and observe, surprisingly, that their
accuracy drops by up to 69.73%. We explore several ways to improve aspect
robustness, and find that adversarial training can improve models' performance
on ARTS by up to 32.85%. Our code and new test set are available at
https://github.com/zhijing-jin/ARTS_TestSet


  The performance of prediction-based assistance for robot teleoperation
degrades in unseen or goal-rich environments due to incorrect or
quickly-changing intent inferences. Poor predictions can confuse operators or
cause them to change their control input to implicitly signal their goal. We
present a new assistance interface for robotic manipulation where an operator
can explicitly communicate a manipulation goal by pointing the end-effector.
The pointing target specifies a region for local pose generation and
optimization, providing interactive control over grasp and placement pose
candidates. We compare the explicit pointing interface to an implicit
inference-based assistance scheme in a within-subjects user study (N=20) where
participants teleoperate a simulated robot to complete a multi-step singulation
and stacking task in cluttered environments. We find that operators prefer the
explicit interface, experience fewer pick failures and report lower cognitive
workload. Our code is available at:
https://github.com/NVlabs/fast-explicit-teleop


  C.~P\'{e}pin recently constructed a semi-factorial compactification of the
N\'{e}ron model of an abelian variety using the flattening technique of
Raynaud--Gruson. Here we prove that an explicit semi-factorial compactification
is a certain moduli space of sheaves --- the family of compactified jacobians.


  A closed subgroup of a semisimple algebraic group is called irreducible if it
lies in no proper parabolic subgroup. In this paper we classify all irreducible
subgroups of exceptional algebraic groups $G$ which are connected, closed and
simple of rank at least $2$. Consequences are given concerning the
representations of such subgroups on various $G$-modules: for example, with one
exception, the conjugacy classes of irreducible simple connected subgroups of
rank at least $2$ are determined by their composition factors on the adjoint
module for $G$.


  We discuss several issues important for experimentally observing Efimov
physics in ultracold quantum gases. By numerically solving the three-boson
Schr\"odinger equation over a broad range of scattering lengths and energies,
and by including model potentials with multiple bound states, we address the
complications of relating experimental observations to available analytic
expressions. These more realistic potentials introduce features that can mask
the predicted Efimov physics at small scattering lengths. They also allow us to
verify that positive and negative scattering lengths are universally connected
only across a pole, not across a zero. Additionally, we show that the spacing
between Efimov features for the relatively small scattering lengths accessible
experimentally fail to precisely follow the geometric progression expected for
Efimov physics. Finally, we emphasize the importance of the short-range
three-body physics in determining the position of Efimov features and show that
theoretically reproducing two-body physics is not generally sufficient to
predict three-body properties quantitatively.


  The paper introduces scaled Bregman distances of probability distributions
which admit non-uniform contributions of observed events. They are introduced
in a general form covering not only the distances of discrete and continuous
stochastic observations, but also the distances of random processes and
signals. It is shown that the scaled Bregman distances extend not only the
classical ones studied in the previous literature, but also the information
divergence and the related wider class of convex divergences of probability
measures. An information processing theorem is established too, but only in the
sense of invariance w.r.t. statistically sufficient transformations and not in
the sense of universal monotonicity. Pathological situations where coding can
increase the classical Bregman distance are illustrated by a concrete example.
In addition to the classical areas of application of the Bregman distances and
convex divergences such as recognition, classification, learning and evaluation
of proximity of various features and signals, the paper mentions a new
application in 3D-exploratory data analysis. Explicit expressions for the
scaled Bregman distances are obtained in general exponential families, with
concrete applications in the binomial, Poisson and Rayleigh families, and in
the families of exponential processes such as the Poisson and diffusion
processes including the classical examples of the Wiener process and geometric
Brownian motion.


  Large language models (LLMs), such as GPT3.5, GPT4 and LLAMA2 perform
surprisingly well and outperform human experts on many tasks. However, in many
domain-specific evaluations, these LLMs often suffer from hallucination
problems due to insufficient training of relevant corpus. Furthermore,
fine-tuning large models may face problems such as the LLMs are not open source
or the construction of high-quality domain instruction is difficult. Therefore,
structured knowledge databases such as knowledge graph can better provide
domain background knowledge for LLMs and make full use of the reasoning and
analysis capabilities of LLMs. In some previous works, LLM was called multiple
times to determine whether the current triplet was suitable for inclusion in
the subgraph when retrieving subgraphs through a question. Especially for the
question that require a multi-hop reasoning path, frequent calls to LLM will
consume a lot of computing power. Moreover, when choosing the reasoning path,
LLM will be called once for each step, and if one of the steps is selected
incorrectly, it will lead to the accumulation of errors in the following steps.
In this paper, we integrated and optimized a pipeline for selecting reasoning
paths from KG based on LLM, which can reduce the dependency on LLM. In
addition, we propose a simple and effective subgraph retrieval method based on
chain of thought (CoT) and page rank which can returns the paths most likely to
contain the answer. We conduct experiments on three datasets: GenMedGPT-5k
[14], WebQuestions [2], and CMCQA [21]. Finally, RoK can demonstrate that using
fewer LLM calls can achieve the same results as previous SOTAs models.


  It is quite exceptional, if it ever happens, that a new conceptual domain be
built from scratch. Usually, it is developed and mastered in interaction, both
positive and negative, with other more operational existing domains. Few
reasoning mechanisms have been proposed to account for the interplay of
different conceptual domains and the transfer of information from one to
another. Analogical reasoning is one, blending is another. This paper presents
a new mechanism, called 'tunnel effect', that may explain, in part, how
scientists and students reason while constructing a new conceptual domain. One
experimental study with high school students and analyses from the history of
science, particularly about the birth of classical thermodynamics, provide
evidence and illustrate this mechanism. The knowledge organization, processes
and conditions for its appearance are detailed and put into the perspective of
a computational model. Specifically, we put forward the hypothesis that two
levels of knowledge, notional and conceptual, cooperate in the scientific
discovery process when a new conceptual domain is being built. The type of
conceptual learning that can be associated with tunnel effect is discussed and
a thorough comparison is made with analogical reasoning in order to underline
the main features of the new proposed mechanism.


  Detecting the presence of mesoscale structures in complex networks is of
primary importance. This is especially true for financial networks, whose
structural organization deeply affects their resilience to events like default
cascades, shocks propagation, etc. Several methods have been proposed, so far,
to detect communities, i.e. groups of nodes whose connectivity is significantly
large. Communities, however do not represent the only kind of mesoscale
structures characterizing real-world networks: other examples are provided by
bow-tie structures, core-periphery structures and bipartite structures. Here we
propose a novel method to detect statistically-signifcant bimodular structures,
i.e. either bipartite or core-periphery ones. It is based on a modification of
the surprise, recently proposed for detecting communities. Our variant allows
for bimodular nodes partitions to be revealed, by letting links to be placed
either 1) within the core part and between the core and the periphery parts or
2) just between the (empty) layers of a bipartite network. From a technical
point of view, this is achieved by employing a multinomial hypergeometric
distribution instead of the traditional (binomial) hypergeometric one; as in
the latter case, this allows a p-value to be assigned to any given
(bi)partition of the nodes. To illustrate the performance of our method, we
report the results of its application to several real-world networks, including
social, economic and financial ones.


  We study the asymptotic properties of distributed consensus algorithms over
switching directed random networks. More specifically, we focus on consensus
algorithms over independent and identically distributed, directed random
graphs, where each agent can communicate with any other agent with some
exogenously specified probability. While different aspects of consensus
algorithms over random switching networks have been widely studied, a complete
characterization of the distribution of the asymptotic value for general
\textit{asymmetric} random consensus algorithms remains an open problem. In
this paper, we derive closed-form expressions for the mean and an upper bound
for the variance of the asymptotic consensus value, when the underlying network
evolves according to an i.i.d. \textit{directed} random graph process. We also
provide numerical simulations that illustrate our results.


  Non-equilibrium vibrational dissociation of CO$_2$ at low
translational-rotational temperatures $T$ is investigated computationally for
conditions of microwave induced plasmas. Semi-analytic treatment of vibrational
relaxation in CO$_2$ in shock tube and acoustic experiments is summarized. A
state-to-state vibrational kinetics model applied for the simulations is
benchmarked and adjusted to the relaxation times obtained in gas dynamic
experiments. The governing parameter $Q/n^2_0$ has been introduced, where $Q$
is the specific volumetric power coupled in plasma and $n_0$ is the initial
number density of CO$_2$. The modelling results indicate a rapid increase of
the rate of the primary dissociation process CO$_2$ + M $\to$ CO + O + M when
$Q/n^2_0$ exceeds some critical value. A simple analytic calculation of $\left(
Q/n^2_0 \right)_{crit}$ is proposed which agrees well with the numerical
results. At $T$=300 K the estimated $\left( Q/n^2_0 \right)_{crit} \eqsim
6\cdot10^{-40}$~W$\cdot$m$^3$.


  Many results about the geometry of the trianguline variety have been obtained
by Breuil-Hellmann-Schraen. Among them, using geometric methods, they have
computed a formula for the dimension of the tangent space of the trianguline
variety at dominant crystalline generic points, which has a conjectural
generalisation to companion (i.e. non-dominant) points. In an earlier work,
they proved a weaker form of this formula under the assumption of modularity
using arithmetic methods. We prove a generalisation of a result of
Bella\"iche-Chenevier in p-adic Hodge theory and use it to extend the
arithmetic methods of Breuil-Hellmann-Schraen to a wide class of companion
points.


  In this paper we compute the number of n degree representations of a group of
order p^3 for p an odd prime and the dimensions of corresponding spaces of
invariant bilinear forms over an algebraically closed field F. We explicitly
discuss about the existence of non-degenerate invariant bilinear forms. The
results are important due to their application in the studies of physical
sciences.


  While Klein paradox is often encountered in the context of scattering of
relativistic particles at a potential barrier, we presently discuss a puzzling
situation that arises with the Klein-Gordon equation for bound states. With the
usual minimal coupling procedure of introducing the interaction potential, a
paradoxical situation arises when the 'hill' becomes a 'well', simulating a
bound-state like situation. The phenomenal phenomenon for bound states is
contrary to the conventional wisdom of quantum mechanics and is analogous to
the well-known Klein paradox, a generic property of relativistic wave
equations.
  PACs Nos. 03.65.Ge, 03.65.Pm


  Delocalization transition is numerically found in a non-Hermitian extension
of a discrete-time quantum walk on a one-dimensional random medium. At the
transition, an eigenvector gets delocalized and at the same time the
corresponding energy eigenvalue (the imaginary unit times the phase of the
eigenvalue of the time-evolution operator) becomes complex. This is in
accordance with a non-Hermitian extension of the random Anderson model in one
dimension, called, the Hatano-Nelson model. We thereby numerically find that
all eigenstates of the Hermitian quantum walk share a common localization
length.


  We assess the metal content of the cool (10^4 K) circumgalactic medium (CGM)
about galaxies at z<1 using an H I-selected sample of 28 Lyman limit systems
(LLS, defined here as absorbers with 16.2<log N(H I)<18.5) observed in
absorption against background QSOs by the Cosmic Origins Spectrograph on-board
the Hubble Space Telescope. The N(H I) selection avoids metallicity biases
inherent in many previous studies of the low-redshift CGM. We compare the
column densities of weakly ionized metal species (e.g., O II, Si II, Mg II) to
N(H I) in the strongest H I component of each absorber. We find that the
metallicity distribution of the LLS (and hence the cool CGM) is bimodal with
metal-poor and metal-rich branches peaking at [X/H]=-1.6 and -0.3 (or about
2.5% and 50% solar metallicities). The cool CGM probed by these LLS is
predominantly ionized. The metal-rich branch of the population likely traces
winds, recycled outflows, and tidally stripped gas; the metal-poor branch has
properties consistent with cold accretion streams thought to be a major source
of fresh gas for star forming galaxies. Both branches have a nearly equal
number of absorbers. Our results thus demonstrate there is a significant mass
of previously-undiscovered cold metal-poor gas and confirm the presence of
metal enriched gas in the CGM of z<1 galaxies.


  Using e+e- -> Ds^-Ds^{*+} and Ds^{*-}Ds^+ interactions at 4170 MeV collected
with the CLEO-c detector, we investigate the semileptonic decays Ds+ -> f0(980)
e+ nu, and Ds+ -> phi e+ nu. By examining the decay rates as functions of the
four-momentum transfer squared, q^2, we measure the ratio [dB/dq^2(Ds+ ->
f0(980) e+ nu) B(f0 -> pi+pi-)]/[dB/dq^2(Ds+ -> phi e+ nu)B(phi -> K+K-)] at
q^2 of zero to be (42 +/- 11)%. This ratio has been predicted to equal the rate
ratio [B(Bs -> J/psi f_0)B(f0 -> pi+pi-)]/[B(Bs -> J/psi phi)B(phi -> K+K-)],
thus indicating that the CP eigenstate J/psi f0 could be useful for measuring
CP violation via Bs mixing. Assuming a simple pole model for the form factor
|f+(q^2)| in the f0 e+ nu decay, we find a pole mass of (1.7 {+4.5} {-0.7} +/-
0.2) GeV. We also determine the f0 mass and width as (977 {+11}{-9} +/- 1) MeV,
and (91{+30}{-22}+/- 3) MeV, respectively. In addition, we present updated
results for B(Ds+ -> f0(980) e+ nu) B(f0 -> pi+pi-)=(0.20 +/- 0.03 +/- 0.01)%,
and B}(Ds+ -> phi e+ nu)=(2.36 +/- 0.23 +/- 0.13)%.


  A diffusion process associated with the real sub-Laplacian $\Delta_b$, the
real part of the complex Kohn-Spencer laplacian $\square_b$, on a strictly
pseudoconvex CR manifold is constructed via the Eells-Elworthy-Malliavin method
by taking advantage of the metric connection due to Tanaka-Webster. Using the
diffusion process and the Malliavin calculus, the heat kernel and the Dirichlet
problem for $\Delta_b$ are studied in a probabilistic manner. Moreover,
distributions of stochastic line integrals along the diffusion process will be
investigated.


  Sliding meshes are a powerful method to treat deformed domains in
computational fluid dynamics, where different parts of the domain are in
relative motion. In this paper, we present an efficient implementation of a
sliding mesh method into a discontinuous Galerkin compressible Navier-Stokes
solver and its application to a large eddy simulation of a 1-1/2 stage turbine.
The method is based on the mortar method and is high-order accurate. It can
handle three-dimensional sliding mesh interfaces with various interface shapes.
For plane interfaces, which are the most common case, conservativity and
free-stream preservation are ensured. We put an emphasis on efficient parallel
implementation. Our implementation generates little computational and storage
overhead. Inter-node communication via MPI in a dynamically changing mesh
topology is reduced to a bare minimum by ensuring a priori information about
communication partners and data sorting. We provide performance and scaling
results showing the capability of the implementation strategy. Apart from
analytical validation computations and convergence results, we present a
wall-resolved implicit LES of the 1-1/2 stage Aachen turbine test case as a
large scale practical application example.


  We study the possibility of the existence of the electric current, formed by
massive electrons and positrons, flowing along an external magnetic field. The
charged fermions are supposed to have nonzero anomalous magnetic moments and
electroweakly interact with background matter. The expression for the current
is obtained on the basis of the exact solution of the Dirac equation in the
corresponding external fields. We demonstrate that, in the state of
equilibrium, such a current is vanishing for any characteristics of the
electron-positron plasma as well as the external fields. Our results are
compared with the recent findings of other authors.


  Understanding how turbulence enhances irreversible scalar mixing in
density-stratified fluids is a central problem in geophysical fluid dynamics.
While isotropic overturning regions are commonly the focus of mixing analyses,
we here investigate whether significant mixing may arise in anisotropic
statically-stable regions of the flow. Focusing on a single forced direct
numerical simulation of stratified turbulence, we analyze spatial correlations
between the vertical density gradient $\partial\rho/\partial z$ and the
dissipation rates of kinetic energy $\epsilon$ and scalar variance $\chi$, the
latter quantifying scalar mixing. The domain is characterized by relatively
well-mixed density layers separated by sharp stable interfaces that are
correlated with high vertical shear. While static instability is most prevalent
within the mixed layers, much of the scalar mixing is localized to the
intervening interfaces, a phenomenon not apparent if considering local static
instability or $\epsilon$ alone. While the majority of the domain is
characterized by the canonical flux coefficient
$\Gamma\equiv\chi/\epsilon=0.2$, often assumed in ocean mixing
parameterizations, extreme values of $\chi$ within the statically-stable
interfaces, associated with elevated $\Gamma$, strongly skew the bulk
statistics. Our findings suggest that current parameterizations of turbulent
mixing may be biased by undersampling, such that the most common, but not
necessarily the most significant, mixing events are overweighted. Having
focused here on a single simulation of stratified turbulence, it is hoped that
our results motivate a broader investigation into the role played by stable
density interfaces in mixing, across a wider range of parameters and forcing
schemes representative of ocean turbulence.


  The possibility to control friction through surface micro texturing could
offer invaluable advantages in many fields, from wear and pollution reduction
in the transportation industry to improved adhesion and grip. Unfortunately,
the texture optimization problem is very hard to solve using traditional
experimental and numerical methods, due to the complexity of the texture
configuration space. In this work, we apply machine learning techniques to
perform the texture optimization, by training a deep neural network to predict,
with extremely high accuracy and speed, the Stribeck curve of a textured
surface in lubricated contact. The deep neural network was used to completely
resolve the mapping between textures and Stribeck curves, enabling a simple
method to solve the texture optimization problem. This work demonstrates the
potential of machine learning techniques in texture optimization for friction
control in lubricated contacts.


  We consider cellular base stations (BSs) equipped with a large number of
antennas and operating in the unlicensed band. We denote such system as massive
MIMO unlicensed (mMIMO-U). We design the key procedures required to guarantee
coexistence between a cellular BS and nearby Wi-Fi devices. These include:
neighboring Wi-Fi channel covariance estimation, allocation of spatial degrees
of freedom for interference suppression, and enhanced channel sensing and data
transmission phases. We evaluate the performance of the so-designed mMIMO-U,
showing that it allows simultaneous cellular and Wi-Fi transmissions by keeping
their mutual interference below the regulatory threshold. The same is not true
for conventional listen-before-talk (LBT) operations. As a result, mMIMO-U
boosts the aggregate cellular-plus-Wi-Fi data rate in the unlicensed band with
respect to conventional LBT, exhibiting increasing gains as the number of BS
antennas grows.


  A Maxwell's demon is a device that gets information and trades it in for
thermodynamic advantage, in apparent (but not actual) contradiction to the
second law of thermodynamics. Quantum-mechanical versions of Maxwell's demon
exhibit features that classical versions do not: in particular, a device that
gets information about a quantum system disturbs it in the process. In
addition, the information produced by quantum measurement acts as an additional
source of thermodynamic inefficiency. This paper investigates the properties of
quantum-mechanical Maxwell's demons, and proposes experimentally realizable
models of such devices.


  The baryon number transfer is studied in elementary and complex hadronic
interactions at the CERN experiment NA49 at the SPS, at 158 AGeV beam energy
(\sqrt{s}=17.2 GeV). A two component picture is proposed, which builds up the
net proton distribution from a target and a projectile component. Using pion
beam, the projectile component is experimentally determined for p+p and p+A
interactions. A similar stopping behaviour of the projectile component is found
for p+A and A+A interactions. Based on these observations, the baryon transfer
is assumed to provide a common scale of inelasticity in p+p, p+A and A+A
interactions. A model-independent way is proposed to predict the pion
multiplicity in A+A.


  The paradigmatic Migdal-Eliashberg theory of the electron-phonon problem is
central to the understanding of superconductivity in conventional metals. This
powerful framework is justified by the smallness of the Debye frequency
relative to the Fermi energy, and allows an enormous simplification of the full
many-body problem. However, superconductivity is found also in many families of
strongly-correlated materials, in which there is no {\it a priori}
justification for the applicability of Eliashberg theory. In these systems,
superconductivity emerges out of an anomalous metallic state, calling for a new
theoretical framework to describe pairing out of a non-Fermi liquid. In this
article, we review two model systems in which such behavior is found: a Fermi
sea coupled to gapless bosonic fluctuations, and a system of fermions with
local, strongly frustrated interactions. In both models, there is a
well-defined limit in which the Eliashberg equations are asymptotically exact
even in the strongly coupled regime. These models thus provide tractable
examples of how superconductivity can emerge in the absence of coherent
electronic quasiparticles; they also demonstrate the surprisingly wide
applicability of the Eliashberg formalism, well beyond the conventional regime
for which it was originally designed.


  We analyze the behavior of the four-terminal resistance, relative to the
two-terminal resistance of an interacting quantum wire with an impurity, taking
into account the invasiveness of the voltage probes. We consider a
one-dimensional Luttinger model of spinless fermions for the wire. We treat the
coupling to the voltage probes perturbatively, within the framework of
non-equilibrium Green function techniques. Our investigation unveils the
combined effect of impurities, electron-electron interactions and invasiveness
of the probes on the possible occurrence of negative resistance.


  Wealth distribution is a complex and critical aspect of any society.
Information exchange is considered to have played a role in shaping wealth
distribution patterns, but the specific dynamic mechanism is still unclear. In
this research, we used simulation-based methods to investigate the impact of
different modes of information exchange on wealth distribution. We compared
different combinations of information exchange strategies and moving
strategies, analyzed their impact on wealth distribution using classic wealth
distribution indicators such as the Gini coefficient. Our findings suggest that
information exchange strategies have significant impact on wealth distribution
and that promoting more equitable access to information and resources is
crucial in building a just and equitable society for all.


  We show that noncompact simply connected harmonic manifolds with volume
density $\Theta_{p}(r) =\sinh ^{n-1} r$ is isometric to the real hyperbolic
space and noncompact simply connected K\"{a}hler harmonic manifold with volume
density $\Theta_{p}(r) =\sinh ^{2n-1} r \cosh r$ is isometric to the complex
hyperbolic space. A similar result is also proved for Quaternionic K\"{a}hler
manifolds. Using our methods we get an alternative proof, without appealing to
the powerful Cheeger-Gromoll splitting theorem, of the fact that every Ricci
flat harmonic manifold is isometric to the euclidean space. Finally a rigidity
result for real hyperbolic space is presented.


  In order to limit the damage of malware on Mac OS X and iOS, Apple uses
sandboxing, a kernel-level security layer that provides tight constraints for
system calls. Particularly used for Apple iOS, sandboxing prevents apps from
executing potentially dangerous actions, by defining rules in a sandbox
profile. Investigating Apple's built-in sandbox profiles is difficult as they
are compiled and stored in binary format. We present SandBlaster, a software
bundle that is able to reverse/decompile Apple binary sandbox profiles to their
original human readable SBPL (SandBox Profile Language) format. We use
SandBlaster to reverse all built-in Apple iOS binary sandbox profiles for iOS
7, 8 and 9. Our tool is, to the best of our knowledge, the first to provide a
full reversing of the Apple sandbox, shedding light into the inner workings of
Apple sandbox profiles and providing essential support for security researchers
and professionals interested in Apple security mechanisms.


  A new approach is presented to the problem of compensating the beam squint
effect arising in wideband terahertz (THz) hybrid massive multiple-input
multiple-output (MIMO) systems, based on the joint optimization of the phase
shifter (PS) and true-time delay (TTD) values under per-TTD device time delay
constraints. Unlike the prior approaches, the new approach does not require the
unbounded time delay assumption; the range of time delay values that a TTD
device can produce is strictly limited in our approach. Instead of focusing on
the design of TTD values, we jointly optimize both the TTD and PS values to
effectively cope with the practical time delay constraints. Simulation results
that illustrate the performance benefits of the new method for the beam squint
compensation are presented. Through simulations and analysis, we show that our
approach is a generalization of the prior TTD-based precoding approaches.


  We study the phase space of periodically modulated gravitational cavity by
means of quantum recurrence phenomena. We report that the quantum recurrences
serve as a tool to connect phase space of the driven system with spectrum in
quantum domain. With the help of quantum recurrences we investigate the
quasi-energy spectrum of the system for a certain fixed modulation strength. In
addition, we study transition of spectrum from discrete to continuum as a
function of modulation strength.


  We utilize copulas to constitute a unified framework for constructing and
optimizing variational proposals in hierarchical Bayesian models. For models
with continuous and non-Gaussian hidden variables, we propose a semiparametric
and automated variational Gaussian copula approach, in which the parametric
Gaussian copula family is able to preserve multivariate posterior dependence,
and the nonparametric transformations based on Bernstein polynomials provide
ample flexibility in characterizing the univariate marginal posteriors.


  Radio pulses emitted in the atmosphere during the air shower development of
high-energy primary cosmic rays were measured during the late 1960ies in the
frequency range from 2 MHz to 520 MHz. Mainly due to difficulties with radio
interference these measurements ceased in the late 1970ies.
  LOFAR (Low Frequency Array) is a new digital radio interferometer under
development. Using high bandwidth ADCs and fast data processing it will be able
to filter out most of the interference. By storing the whole waveform
information in digital form one can analyze transient events like air showers
even after they have been recorded.
  To test this new technology and to demonstrate its ability to measure air
showers a "LOFAR Prototype Station" (LOPES) is set up to operate in conjunction
with an existing air shower array (KASCADE-Grande).
  The first phase consisting of 10 antennas is already running. It operates in
the frequency range of 40 to 80 MHz, using simple short dipole antennas and
direct 2nd Nyquist sampling of the incoming wave. It has proven to be able to
do simple astronomical measurements, like imaging of a solar burst. It has also
demonstrated how digital interference suppression and beamforming can overcome
the problem of radio interference and pick out air shower events.


  A theory is constructed to describe the zero-temperature jamming transition
as the density of repulsive soft spheres is increased. Local mechanical
stability imposes a constraint on the minimum number of bonds per particle; we
argue that this constraint suggests an analogy to $k$-core percolation. The
latter model can be solved exactly on the Bethe lattice, and the resulting
transition has a mixed first-order/continuous character. The exponents
characterizing the continuous part appear to be the same as for the jamming
transition. Finally, numerical simulations suggest that in finite dimensions
the $k$-core transition can be discontinuous with a nontrivial diverging
correlation length.


  Let X be a minimal complex surface of general type such that its image via
the canonical map is a surface; we denote by d the degree of the canonical map.
  In this expository work, first of all we recall the known possibilities for
the canonical image and for d when the canonical map is not birational, which
are quite a few, and then we consider the question of producing concrete
examples for all of them.
  We present the two main methods of construction of such examples and we give
several instances of their application. We end the paper outlining the state of
the art on this topic and raising several questions.


  The PHENIX experiment reports systematic measurements at the Relativistic
Heavy Ion Collider of $\phi$-meson production in asymmetric Cu$+$Au collisions
at $\sqrt{s_{_{NN}}}$=200 GeV and in U$+$U collisions at $\sqrt{s_{_{NN}}}$=193
GeV. Measurements were performed via the $\phi\rightarrow K^{+}K^{-}$ decay
channel at midrapidity $|\eta|<0.35$. Features of $\phi$-meson production
measured in Cu$+$Cu, Cu$+$Au, Au$+$Au, and U$+$U collisions were found to not
depend on the collision geometry, which was expected because the yields are
averaged over the azimuthal angle and follow the expected scaling with
nuclear-overlap size. The elliptic flow of the $\phi$ meson in Cu$+$Au,
Au$+$Au, and U$+$U collisions scales with second-order-participant eccentricity
and the length scale of the nuclear-overlap region (estimated with the number
of participating nucleons). At moderate $p_T$, $\phi$-meson production measured
in Cu$+$Au and U$+$U collisions is consistent with coalescence-model
predictions, whereas at high $p_T$ the production is in agreement with
expectations for in-medium energy loss of parent partons prior to their
fragmentation. The elliptic flow for $\phi$ mesons measured in Cu$+$Au and
U$+$U collisions is well described by a (2+1)D viscous-hydrodynamic model with
specific-shear viscosity $\eta/s=1/4\pi$.


  We begin an investigation of inhomogeneous structures in holographic
superfluids. As a first example, we study domain wall like defects in the 3+1
dimensional Einstein-Maxwell-Higgs theory, which was developed as a dual model
for a holographic superconductor. In [1], we reported on such "dark solitons"
in holographic superfluids. In this work, we present an extensive numerical
study of their properties, working in the probe limit. We construct dark
solitons for two possible condensing operators, and find that both of them
share common features with their standard superfluid counterparts. However,
both are characterized by two distinct coherence length scales (one for order
parameter, one for charge condensate). We study the relative charge depletion
factor and find that solitons in the two different condensates have very
distinct depletion characteristics. We also study quasiparticle excitations
above the holographic superfluid, and find that the scale of the excitations is
comparable to the soliton coherence length scales.


  We present a novel approach to estimate the delay observed between the
occurrence and reporting of rape crimes. We explore spatial, temporal and
social effects in sparse aggregated (area-level) and high-dimensional
disaggregated (event-level) data for New York and Los Angeles. Focusing on
inference, we apply Gradient Boosting and Random Forests to assess predictor
importance, as well as Gaussian Processes to model spatial disparities in
reporting times. Our results highlight differences and similarities between the
two cities. We identify at-risk populations and communities which may be
targeted with focused policies and interventions to support rape victims,
apprehend perpetrators, and prevent future crimes.


  Muon spin rotation measurements have been performed on a powder sample of
a-RuCl3, a layered material which previously has been proposed to be a quantum
magnet on a honeycomb lattice close to a quantum spin liquid ground state. Our
data reveal two distinct phase transitions at 11 K and 14 K which we interpret
as originating from the onset of three-dimensional order and in-plane magnetic
order, respectively. We identify, with the help of density functional theory
calculations, likely muon stopping sites and combine these with dipolar field
calculations to show that the two measured muon rotation frequencies are
consistent with two inequivalent muon sites within a zig-zag antiferromagnetic
structure proposed previously.


  Here we report a scanning tunneling microscopy (STM) and spectroscopy (STS)
study in the superconducting state of 2H-NbS2. We directly visualize the
existence of incommensurate charge density wave (CDW) that is pinned by atomic
impurities. In strong tunneling conditions, the incommensurate CDW is de-pinned
from impurities by the electric field from STM tip. We perform STM-based
inelastic tunneling spectroscopy (IETS) to detect phonon excitations in 2H-NbS2
and measure the influence of atomic impurities on local phonon excitations. In
comparison with the calculated vibrational density of states in 2H-NbS2, we
find two branches of phonon excitations which correspond to the vibrations of
Nb ions and S ions, and the strength of the local phonon excitations is
insensitive to the atomic impurities. Our results demonstrate the coexistence
of incommensurate CDW and superconductivity in 2H-NbS2, and open the way of
detecting atomic-scale phonon excitations in transition metal dichalcogenides
with STM-based IETS.


  Context: BL Lac objects are a rare class of active galactic nuclei that
typically show featureless optical spectra that make it difficult to estimate
the redshift. A novel method for estimating the redshift of BL Lac objects has
recently been proposed which assumes that these objects typically reside in
groups of galaxies.
  Aims: The aim of this work is to estimate the fraction of BL Lac objects that
reside in groups of galaxies.
  Methods: We use a sample of groups (M12 catalogue) selected by applying a
friends-of-friends algorithm in the SDSS DR12. Galaxies in the M12 sample were
cross-correlated with the sample of blazars in the BZCAT.
  Results: We found that 121 galaxies in the M12 catalogue are blazars in the
BZCAT sample, all but one are BL Lac objects, and a large fraction are
classified as BL Lac-galaxy dominated. Analysing the fraction of galaxies in
groups as a function of redshift we have estimated a correction factor that
takes into account the typical incompleteness of the catalogues based on the
friends-of-friends algorithm. Once this factor was applied to the sample of BL
Lac objects with a counterpart in the M12 catalogue, we found that the
percentage of BL Lac objects in groups is $\gtrsim 67 \pm 8\%$.
  Conclusions: The high rate of BL Lac objects in groups found in this work
strongly supports a recent method that has successfully estimated the redshift
of BL Lac objects with featureless spectra.


  We show that in a parametric family of linear recurrence sequences
$a_1(\alpha) f_1(\alpha)^n + \ldots + a_k(\alpha) f_k(\alpha)^n$ with the
coefficients $a_i$ and characteristic roots $f_i$, $i=1, \ldots,k$, given by
rational functions over some number field, for all but a set of $\alpha$ of
bounded height in the algebraic closure of $\mathbb Q$, the Skolem problem is
solvable, and the existence of a zero in such a sequence can be effectively
decided. We also discuss several related questions.


  The dependence of the nuclear force on standard model parameters plays an
important role in bounding time and space variations of fundamental couplings
over cosmological time scales. We discuss the quark-mass dependence of deuteron
and di-neutron binding in a systematic chiral expansion. The leading quark-mass
dependence of the nuclear force arises from one-pion exchange and from local
quark-mass dependent four-nucleon operators with coefficients that are
presently unknown. By varying these coefficients while leaving nuclear
observables at the physical values of the quark masses invariant, we find
scenarios where two-nucleon physics depends both weakly and strongly on the
quark masses. While the determination of these coefficients is an exciting
future opportunity for lattice QCD, we conclude that, at present, bounds on
time and space variations of fundamental parameters from the two-nucleon sector
are much weaker than previously claimed. This brings into question the
reliability of coupling-constant bounds derived from more complex nuclei and
nuclear processes.


  We have calculated the shear viscosity coefficient $\eta$ of the strongly
interacting matter in the relaxation time approximation, where a quasi particle
description of quarks with its dynamical mass is considered from NJL model. Due
to the thermodynamic scattering of quarks with pseudo scalar type condensate
(i.e. pion), a non zero Landau damping will be acquired by the propagating
quarks. This Landau damping may be obtained from the Landau cut contribution of
the in-medium self-energy of quark-pion loop, which is evaluated in the
framework of real-time thermal field theory.


  We generalize the big-bang model in a previous paper by extending the real
vacuum scalar field to a complex vacuum scalar field, within the FLRW
framework. The phase dynamics of the scalar field, which makes the universe a
superfluid, is described in terms of a density of quantized vortex lines, and a
tangle of vortex lines gives rise to quantum turbulence. We propose that all
the matter in the universe was created in the turbulence, through reconnection
of vortex lines, a process necessary for the maintenance of the vortex tangle.
The vortex tangle grows and decays, and its lifetime is the era of inflation.
These ideas are implemented in a set of closed cosmological equations that
describe the cosmic expansion driven by the scalar field on the one hand, and
the vortex-matter dynamics on the other. We show how these two aspects decouple
from each other, due to a vast difference in energy scales. The model is not
valid beyond the inflation era, but the universe remains a superfluid
afterwards. This gives rise to observable effects in the present universe,
including dark matter, galactic voids, non-thermal filaments, and cosmic jets.


  Let $f \colon (X,\Delta) \to Y$ be a fibration such that $K_X + \Delta$ is
torsion along the fibres of $f$. Assume that $Y$ has dimension 2, or that $Y$
has dimension 3 and the fibres have dimension at most 3. Then the restriction
of the moduli part to its augmented base locus is semiample.


  We present spatial, temporal and spectral analyses of ROSAT Position
Sensitive Proportional Counter (PSPC) observations of the Seyfert 1 galaxies
Ark 564, NGC 985, Kaz 163, Mrk 79 and RX J2256.6+0525. Ark 564 is a powerful
narrow-line Seyfert 1 with strong Fe II emission. Several similar narrow-line
Seyfert 1 galaxies have recently been found to have remarkably steep soft X-ray
continua as well as rapid X-ray variability. We find that Ark 564 also has a
very steep ($\Gamma > 3$) 0.1--2.5 keV spectrum and varies by $\sim 20$ per
cent in 1500 s. We examine models for Ark 564 in light of both its X-ray and
optical characteristics, and suggest a possible connection between the steep
X-ray spectra of narrow-line Seyfert 1 galaxies and their narrow lines. NGC 985
has a large soft excess, a warm absorber, or both. The three other Seyferts
have systematically steeper spectra than are typically observed for Seyferts in
higher energy Ginga data, indicating that they also harbour further spectral
complexity. Kaz 163 shows $\sim 45$ per cent intensity variability in the
0.1--2.5 keV band, and Mrk 79 shows evidence for variability as well.


  Channel estimation is challenging for millimeter-wave (mmWave) massive MIMO
with hybrid precoding, since the number of radio frequency (RF) chains is much
smaller than that of antennas. Conventional compressive sensing based channel
estimation schemes suffer from severe resolution loss due to the channel angle
quantization. To improve the channel estimation accuracy, we propose an
iterative reweight (IR)-based super-resolution channel estimation scheme in
this paper. By optimizing an objective function through the gradient descent
method, the proposed scheme can iteratively move the estimated angle of
arrivals/departures (AoAs/AoDs) towards the optimal solutions, and finally
realize the super-resolution channel estimation. In the optimization, a weight
parameter is used to control the tradeoff between the sparsity and the data
fitting error. In addition, a singular value decomposition (SVD)-based
preconditioning is developed to reduce the computational complexity of the
proposed scheme. Simulation results verify the better performance of the
proposed scheme than conventional solutions.


  The standard cosmological model determined from the accurate cosmic microwave
background measurements made by the Planck satellite implies a value of the
Hubble constant $H_0$ that is $4.2$ standard deviations lower than the one
determined from Type Ia supernovae. The Planck best fit model also predicts
higher values of the matter density fraction $\Omega_m$ and clustering
amplitude $S_8$ compared to those obtained from the Dark Energy Survey Year 1
data. Here we show that accounting for the enhanced recombination rate due to
additional small-scale inhomogeneities in the baryon density may solve both the
$H_0$ and the $S_8-\Omega_m$ tensions. The additional baryon inhomogeneities
can be induced by primordial magnetic fields present in the plasma prior to
recombination. The required field strength to solve the Hubble tension is just
what is needed to explain the existence of galactic, cluster, and extragalactic
magnetic fields without relying on dynamo amplification. Our results show clear
evidence for this effect and motivate further detailed studies of primordial
magnetic fields, setting several well-defined targets for future observations.


  The Floquet Hamiltonian has often been used to describe a time-periodic
system. Nevertheless, because the Floquet Hamiltonian depends on a micro-motion
parameter, the Floquet Hamiltonian with a fixed micro-motion parameter cannot
faithfully represent a driven system, which manifests as the anomalous edge
states. Here we show that an accurate description of a Floquet system requires
a set of Hamiltonian exhausting all values of the micro-motion parameter, and
this micro-motion parameter can be viewed as an extra synthetic dimension of
the system. Therefore, we show that a $d$-dimensional Floquet system can be
described by a $d+1$-dimensional static Hamiltonian, and the advantage of this
representation is that the periodic boundary condition is automatically imposed
along the extra-dimension, which enables a straightforward definition of
topological invariants. The topological invariant in the $d+1$-dimensional
system can ensure a $d-1$-dimensional edge state of the $d$-dimensional Floquet
system. Here we show two examples where the topological invariant is a
three-dimensional Hopf invariant. We highlight that our scheme of classifying
Floquet topology on the micro-motion space is different from the previous
classification of Floquet topology on the time space.


  Virtual assistants have been widely used by mobile phone users in recent
years. Although their capabilities of processing user intents have been
developed rapidly, virtual assistants in most platforms are only capable of
handling pre-defined high-level tasks supported by extra manual efforts of
developers. However, instance-level user intents containing more detailed
objectives with complex practical situations, are yet rarely studied so far. In
this paper, we explore virtual assistants capable of processing instance-level
user intents based on pixels of application screens, without the requirements
of extra extensions on the application side. We propose a novel cross-modal
deep learning pipeline, which understands the input vocal or textual
instance-level user intents, predicts the targeting operational area, and
detects the absolute button area on screens without any metadata of
applications. We conducted a user study with 10 participants to collect a
testing dataset with instance-level user intents. The testing dataset is then
utilized to evaluate the performance of our model, which demonstrates that our
model is promising with the achievement of 64.43% accuracy on our testing
dataset.


  Wireless blockchain networks have played an important role in many network
scenarios, among which wireless Practical Byzantine Fault Tolerance (PBFT)
consensus is regarded as one of the most important consensus mechanisms. It
enables nodes in wireless networks to reach consistency without any trusted
entity. However, due to the instability of wireless communication links, the
reliability of the PBFT consensus will be seriously affected. Meanwhile, it is
difficult for nodes in wireless scenarios to obtain a timely energy supply. The
high-energy-consumption blockchain functions will quickly consume the power of
nodes, thus, affecting consensus performance. Fortunately, the symbiotic radio
(SR) system enabled by cognitive backscatter communications can provide a
solution to the above problems. In SR, the secondary transmitter (STx)
transmits messages by modulating its information over the radio frequency (RF)
signal of the primary transmitter (PTx) with extremely low energy consumption,
and the STx can provide multipath gain to the PTx in return. In our paper, we
propose the symbiotic PBFT (S-PBFT) consensus benefited from the mutualistic
transmission in SR, which can increase the consensus security by 54.82%, and
save energy consumption by about 10%.


  Multiplayer Online Battle Arena (MOBA) games are among the most played
digital games in the world. In these games, teams of players fight against each
other in arena environments, and the gameplay is focused on tactical combat.
Mastering MOBAs requires extensive practice, as is exemplified in the popular
MOBA Defence of the Ancients 2 (DotA 2). In this paper, we present three
data-driven measures of spatio-temporal behavior in DotA 2: 1) Zone changes; 2)
Distribution of team members and: 3) Time series clustering via a fuzzy
approach. We present a method for obtaining accurate positional data from DotA
2. We investigate how behavior varies across these measures as a function of
the skill level of teams, using four tiers from novice to professional players.
Results indicate that spatio-temporal behavior of MOBA teams is related to team
skill, with professional teams having smaller within-team distances and
conducting more zone changes than amateur teams. The temporal distribution of
the within-team distances of professional and high-skilled teams also generally
follows patterns distinct from lower skill ranks.


  Although Zermelo-Fraenkel set theory (ZFC) is generally accepted as the
appropriate foundation for modern mathematics, proof theorists have known for
decades that virtually all mainstream mathematics can actually be formalized in
much weaker systems which are essentially number-theoretic in nature. Feferman
has observed that this severely undercuts a famous argument of Quine and Putnam
according to which set theoretic platonism is validated by the fact that
mathematics is "indispensable" for some successful scientific theories (since
in fact ZFC is not needed for the mathematics that is currently used in
science).
  I extend this critique in three ways: (1) not only is it possible to
formalize core mathematics in these weaker systems, they are in important ways
better suited to the task than ZFC; (2) an improved analysis of the
proof-theoretic strength of predicative theories shows that most if not all of
the already rare examples of mainstream theorems whose proofs are currently
thought to require metaphysically substantial set-theoretic principles actually
do not; and (3) set theory itself, as it is actually practiced, is best
understood in formalist, not platonic, terms, so that in a real sense *set
theory is not even indispensable for set theory*. I also make the point that
even if ZFC is consistent, there are good reasons to suspect that some
number-theoretic assertions provable in ZFC may be false. This suggests that
set theory should not be considered central to mathematics.


  Pre-shared keys (PSK) have been widely used in network security. Nonetheless,
existing PSK solutions are not scalable. Moreover, whenever a new user joins a
network, PSK requires an existing user to get a new key before they are able to
communicate with the new user. The key issue is how to distribute the PSK
between different users. Here, we solve this problem by proposing a new
protocol called Distributed Symmetric Key Establishment (DSKE). DSKE has the
advantage of being scalable. Unlike standard public key infrastructure (PKI)
which relies on computational assumptions, DSKE provides information-theoretic
security in a universally composable security framework. Specifically, we prove
the security (correctness and confidentiality) and robustness of this protocol
against a computationally unbounded adversary, who additionally may have fully
compromised a bounded number of the intermediaries and can eavesdrop on all
communication. DSKE also achieves distributed trust through secret sharing.
  We present several implementations of DSKE in real environments, such as
providing client services to link encryptors, network encryptors, and mobile
phones, as well as the implementation of intermediaries, called Security Hubs,
and associated test data as evidence for its versatility. As DSKE is highly
scalable in a network setting with no distance limit, it is expected to be a
cost-effective quantum-safe cryptographic solution to the network security
threat presented by quantum computers.


  We observe that a probability distribution supported by $\mathbb{N}$, induces
a representation of real numbers in [0, 1) with digits in $\mathbb{N}$. We
first study the Hausdorff dimension of sets with prescribed digits with respect
to these representations. Than we determine the prevalent frequency of digits
and the Hausdorff dimension of sets with prescribed frequencies of digits. As
examples we consider the geometric distribution, the Poisson distribution and
the zeta distribution.


  In this note, we show that the Lyapunov exponents of mixed products of random
truncated Haar unitary and complex Ginibre matrices are asymptotically given by
equally spaced `picket-fence' statistics. We discuss how these statistics
should originate from the connection between random matrix products and
multiplicative Brownian motion on $\operatorname{GL}_n(\mathbb{C})$, analogous
to the connection between discrete random walks and ordinary Brownian motion.
Our methods are based on contour integral formulas for products of classical
matrix ensembles from integrable probability.


  This article documents the performance of the ATLAS muon identification and
reconstruction using the first LHC dataset recorded at $\sqrt{s}$ = 13 TeV in
2015. Using a large sample of $J/\psi\to\mu\mu$ and $Z\to\mu\mu$ decays from
3.2 fb$^{-1}$ of $pp$ collision data, measurements of the reconstruction
efficiency, as well as of the momentum scale and resolution, are presented and
compared to Monte Carlo simulations. The reconstruction efficiency is measured
to be close to $99\%$ over most of the covered phase space ($|\eta|<2.5$ and $5
< p_{T} < 100$ GeV). The isolation efficiency varies between $93\%$ and $100\%$
depending on the selection applied and on the momentum of the muon. Both
efficiencies are well reproduced in simulation. In the central region of the
detector, the momentum resolution is measured to be $1.7\%$ ($2.3\%$) for muons
from $J/\psi\to\mu\mu$ ($Z\to\mu\mu$) decays, and the momentum scale is known
with an uncertainty of $0.05\%$. In the region $|\eta |>2.2$, the $p_{T} $
resolution for muons from $Z\to\mu\mu$ decays is $2.9\%$ while the precision of
the momentum scale for low-$p_{T} $ muons from $J/\psi\to\mu\mu$ decays is
about $0.2\%$.


  Recent work on the properties of superluminal waves in pulsar winds is
summarized. It is speculated that these waves play an important role in the
termination shock that divides the wind from the surrounding nebula.


  A hot topic in data center design is to envision geo-distributed
architectures spanning a few sites across wide area networks, allowing more
proximity to the end users and higher survivability, defined as the capacity of
a system to operate after failures. As a shortcoming, this approach is subject
to an increase of latency between servers, caused by their geographic
distances. In this paper, we address the trade-off between latency and
survivability in geo-distributed data centers, through the formulation of an
optimization problem. Simulations considering realistic scenarios show that the
latency increase is significant only in the case of very strong survivability
requirements, whereas it is negligible for moderate survivability requirements.
For instance, the worst-case latency is less than 4~ms when guaranteeing that
80% of the servers are available after a failure, in a network where the
latency could be up to 33 ms.


  We construct a proposal for effective bosonic field theory at order $
\alpha'^3 $ in twelve dimensions, whose compactification on a circle and on a
torus respectively yields eleven-dimensional and type IIB supergravity theories
at eight-derivative level. The couplings $ ({\partial {G_5}})^2 R^2 $, $
({\partial {F_4}})^2 R^2 $, $ ({\partial {F_4}})^4 $, $ ({\partial {G_5}})^4 $
and $ ({\partial {G_5}})^2({\partial {F_4}})^2 $ in twelve-dimensional
supergravity are determined with this requirement that an ansatz of these
couplings should admits a consistent truncation to the eleven-dimensional and
type IIB supergravity theories. The self-duality condition of the five-form
field strength in twelve dimensions is also understood by considering the RR
five-form field strength of type IIB theory at linear order.


  There is a big gap between the charming principles ideas and the real
implementation of a diagnostic. In this lecture we review some details that
make the difference between a good and bad measurement, highlighting also the
relation between the measured quantities and the real ones.


  Remote sensing image change captioning (RSICC) aims to articulate the changes
in objects of interest within bi-temporal remote sensing images using natural
language. Given the limitations of current RSICC methods in expressing general
features across multi-temporal and spatial scenarios, and their deficiency in
providing granular, robust, and precise change descriptions, we introduce a
novel change captioning (CC) method based on the foundational knowledge and
semantic guidance, which we term Semantic-CC. Semantic-CC alleviates the
dependency of high-generalization algorithms on extensive annotations by
harnessing the latent knowledge of foundation models, and it generates more
comprehensive and accurate change descriptions guided by pixel-level semantics
from change detection (CD). Specifically, we propose a bi-temporal SAM-based
encoder for dual-image feature extraction; a multi-task semantic aggregation
neck for facilitating information interaction between heterogeneous tasks; a
straightforward multi-scale change detection decoder to provide pixel-level
semantic guidance; and a change caption decoder based on the large language
model (LLM) to generate change description sentences. Moreover, to ensure the
stability of the joint training of CD and CC, we propose a three-stage training
strategy that supervises different tasks at various stages. We validate the
proposed method on the LEVIR-CC and LEVIR-CD datasets. The experimental results
corroborate the complementarity of CD and CC, demonstrating that Semantic-CC
can generate more accurate change descriptions and achieve optimal performance
across both tasks.


  We prove that $K_G<\frac{\pi}{2\log(1+\sqrt{2})}$, where $K_G$ is the
Grothendieck constant.


  The geometric quantization problem is considered from the point of view of
the Davies and Lewis approach to quantum mechanics. The influence of the
measuring device is accounted in the classical and quantum case and it is shown
that the conditions of the measurement define the type of quantization (Weyl,
normal, antinormal, etc.). The quantum states and quantum operators are
obtained by means of the projection, defined from the system of generalized
coherent states.


  Recent grassroots movements have suggested that online social networks might
play a key role in their organization, as adherents have a fast, many-to-many,
communication channel to help coordinate their mobilization. The structure and
dynamics of the networks constructed from the digital traces of protesters have
been analyzed to some extent recently. However, less effort has been devoted to
the analysis of the semantic content of messages exchanged during the protest.
Using the data obtained from a microblogging service during the brewing and
active phases of the 15M movement in Spain, we perform the first large scale
test of theories on collective emotions and social interaction in collective
actions. Our findings show that activity and information cascades in the
movement are larger in the presence of negative collective emotions and when
users express themselves in terms related to social content. At the level of
individual participants, our results show that their social integration in the
movement, as measured through social network metrics, increases with their
level of engagement and of expression of negativity. Our findings show that
non-rational factors play a role in the formation and activity of social
movements through online media, having important consequences for viral
spreading.


  We analytically study the expansion of a Bose-Einstein condensate in a
ring-shaped trap with an increasing central radius. The evolution of the ground
state is described using a scaling transform. Additionally, the dynamics of
excited azimuthal modes over the varying ground state is analyzed through a
generalization of the Bogoliubov-de Gennes approach. Our results explain some
of the features observed in recent experiments focused on testing the
applicability of the system as a parallel of cosmological inflationary models.
The radial dynamics, which corresponds to the inflaton field of the
cosmological counterpart, is analytically characterized: The expansion is found
to induce the oscillatory displacement of the condensate as well as the coupled
variation of the radial and vertical widths. Our findings account also for the
observed redshift and emergence of the Hubble friction in the evolution of
initially-prepared azimuthal modes. Our description, which traces the role of
the different components of the setup in the expansion, enhances the
controllability, and, therefore, the potential of the system as a ground for
emulating the inflationary dynamics of cosmological models.


  The hitting partitions are random partitions that arise from the
investigation of so-called hitting scenarios of max-infinitely-divisible
(max-i.d.)~distributions. We study a class of max-i.d.~laws with exchangeable
hitting partitions obtained by size-biased sampling from the jumps of a L\'evy
subordinator. We obtain explicit formulae for the distributions of these
partitions in the case of the multivariate $\alpha$-logistic and another family
of exchangeable max-i.d.\ distributions. Specifically, the hitting partitions
for these two cases are shown to coincide with the well-known
Poisson--Dirichlet partitions ${\rm PD}(\alpha,0),\ \alpha\in (0,1)$ and ${\rm
PD}(0,\theta),\ \theta>0$.


  The concept of topological persistence, introduced recently in computational
topology, finds applications in studying a map in relation to the topology of
its domain. Since its introduction, it has been extended and generalized in
various directions. However, no attempt has been made so far to extend the
concept of topological persistence to a generalization of `maps' such as
cocycles which are discrete analogs of closed differential forms, a well known
concept in differential geometry. We define a notion of topological persistence
for 1-cocycles in this paper and show how to compute its relevant numbers. It
turns out that, instead of the standard persistence, one of its variants which
we call level persistence can be leveraged for this purpose. It is worth
mentioning that 1-cocyles appear in practice such as in data ranking or in
discrete vector fields.


  We have studied the phase diagram of a quasi-two-dimensional interacting Bose
gas at zero temperature in the presence of random potential created by laser
speckles. The superfluid fraction and the fraction of particles with zero
momentum are obtained within the mean-field Gross-Pitaevskii theory and in
diffusion Monte Carlo simulations. We find a transition from the superfluid to
the insulating state, when the strength of the disorder grows. Estimations of
the critical parameters are compared with the predictions of the percolation
theory in the Thomas-Fermi approximation. Analytical expressions for the
zero-momentum fraction and the superfluid fraction are derived in the limit of
weak disorder and weak interactions within the framework of the Bogoliubov
theory. Limits of validity of various approximations are discussed.


  We observed the low-mass X-ray binary and Z source GX 17+2 with the Rossi
X-ray Timing Explorer during 6-8 Feb 1997, 1-4 Apr 1997, and 26-27 Jul 1997.
The X-ray color-color diagram shows a clear Z track. Two simultaneous kHz
quasi-periodic oscillations (QPOs) are present in each observation, whose
frequencies are well correlated with the position of the source on the Z-track.
At the left end of the horizontal branch (HB) only the higher frequency peak is
observed, at 645+/-9 Hz, with an rms amplitude of 5.7+/-0.5%, and a FWHM of
183+/-35 Hz. When the source moves down the Z track to the upper normal branch
the frequency of the kHz QPO increases to 1087+/-12 Hz, and the rms amplitude
and FWHM decrease by a factor 2. Further down the Z the QPO becomes
undetectable, with rms upper limits of typically 2.0%. Halfway down the HB a
second QPO appears in the power spectra with a frequency of 480+/-23 Hz. The
frequency of this QPO also increases when the source moves along the Z track,
up to 781+/-11 Hz halfway down the normal branch, while the rms amplitude and
FWHM stay approximately constant at 2.5% and 70 Hz. The QPO frequency
difference is constant at 293.5+/-7.5 Hz. Simultaneously with the kHz QPOs we
detect HB QPOs (HBOs). The simultaneous presence of HBOs and kHz QPOs excludes
the magnetospheric beat-frequency model as the explanation for at least one of
these two phenomena.


  We introduce highly efficient online nonlinear regression algorithms that are
suitable for real life applications. We process the data in a truly online
manner such that no storage is needed, i.e., the data is discarded after being
used. For nonlinear modeling we use a hierarchical piecewise linear approach
based on the notion of decision trees where the space of the regressor vectors
is adaptively partitioned based on the performance. As the first time in the
literature, we learn both the piecewise linear partitioning of the regressor
space as well as the linear models in each region using highly effective second
order methods, i.e., Newton-Raphson Methods. Hence, we avoid the well known
over fitting issues by using piecewise linear models, however, since both the
region boundaries as well as the linear models in each region are trained using
the second order methods, we achieve substantial performance compared to the
state of the art. We demonstrate our gains over the well known benchmark data
sets and provide performance results in an individual sequence manner
guaranteed to hold without any statistical assumptions. Hence, the introduced
algorithms address computational complexity issues widely encountered in real
life applications while providing superior guaranteed performance in a strong
deterministic sense.


  To date, rings are found around a Centaur (10199) Chariklo, trans-neptunian
objects (TNOs) (136108) Haumea, and (50000) Quaoar. These discoveries suggest
that asteroidal ring systems may be common, particularly in the outer solar
system. Since collisions are a ubiquitous and fundamental evolutionary process
throughout the solar system, we conjecture that asteroidal ring systems must
have experienced close encounters with small objects as part of their
evolutionary process. Here, we investigate the response of ring systems when
they experience gravitational disturbance by a close encounter with another
small object, by calculating the change in eccentricity and the fraction of
lost ring particles. We find that a perturber needs to be as massive as or more
massive than the ringed object, and needs to pass in the immediate vicinity of
the ring in order to cause significant disruption. The change in eccentricity
expected for Chariklo's inner ring and Quaoar's outer ring agrees with the
analytical expression derived from the impulse approximation, while that for
Haumea's ring agrees with the analytical expression called "exponential
regime". If we define a lifetime of a ring as the mean time to experience
disruptive close encounters that can raise the eccentricity of ring particles
greater than 0.1, the lifetime for ring systems around Chariklo, Haumea, and
Quaoar are >10^4 Gyr. We conclude that ring systems around Chariklo, Haumea,
and Quaoar are highly unlikely to suffer from close encounters with another
small object even if those systems are as old as 4 Gyr. We also find that the
lifetime is shorter for smaller ringed objects, and it still exceeds 4 Gyr for
km-sized ringed objects in the outer solar system. Therefore, regardless of the
size of ringed objects, asteroidal ring systems in the outer solar system are
unlikely to suffer severe damage by close encounter with a small object.


  Duality transformations play a very important role in theoretical physics. In
this paper I propose new duality transformations for fermionic theories. They
map the strong coupling regime of one theory to the weak coupling regime of
another theory. These transformations are based on the functional integral
representation of the fermionic theories in terms of Grassmann variables and
rely heavily on the properties of Grassmann variables. Potential applications
include the study of the strong coupling phase of the two dimensional Hubbard
model.