  Strictly positive logics recently attracted attention both in the description
logic and in the provability logic communities for their combination of
efficiency and sufficient expressivity. The language of Reflection Calculus RC
consists of implications between formulas built up from propositional variables
and constant `true' using only conjunction and diamond modalities which are
interpreted in Peano arithmetic as restricted uniform reflection principles.
  We extend the language of RC by another series of modalities representing the
operators associating with a given arithmetical theory T its fragment
axiomatized by all theorems of T of arithmetical complexity $\Pi^0_n$, for all
n>0. We note that such operators, in a precise sense, cannot be represented in
the full language of modal logic.
  We formulate a formal system RC$^\nabla$ extending RC that is sound and, as
we conjecture, complete under this interpretation. We show that in this system
one is able to express iterations of reflection principles up to any ordinal
$<\epsilon_0$. On the other hand, we provide normal forms for its variable-free
fragment. Thereby, the variable-free fragment is shown to be decidable and
complete w.r.t. its natural arithmetical semantics.
  Whereas the normal forms for the variable-free formulas of RC correspond in a
unique way to ordinals below $\epsilon_0$, the normal forms of RC$^\nabla$ are
more general. It turns out that they are related in a canonical way to the
collections of proof-theoretic ordinals of (bounded) arithmetical theories for
each complexity level $\Pi^0_{n+1}$.
  Finally, we present an algebraic universal model for the variable-free
fragment of RC$^\nabla$ based on Ignatiev's Kripke frame. Our main theorem
states the isomorphism of several natural representations of this algebra.


  We investigate two key representative semiclassical approaches for
propagating resonant energy transfer between a pair of electronic two-level
systems (donor and acceptor) with coupled Maxwell-Liouville equations. On the
one hand, when the electromagnetic (EM) field is treated classically and
Coulomb interactions are treated quantum-mechanically, we find that a
quantum-classical mismatch leads to a violation of causality, i.e., the
acceptor can be excited before the retarded EM field arrives. On the other
hand, if we invoke a classical intermolecular Coulomb operator, we find that
the energy transfer in the near field loses quantitative accuracy compared with
F\"orster theory, even though causality is strictly obeyed. Thus, our work
raises a fundamental paradox when choosing a semiclassical electrodynamics
algorithm. Namely, which is more important: Accurate short range interactions
or long range causality? Apparently, one cannot have one's cake and eat it too.


  Work in the Open Archives Initiative - Object Reuse and Exchange (OAI-ORE)
focuses on an important aspect of infrastructure for eScience: the
specification of the data model and a suite of implementation standards to
identify and describe compound objects. These are objects that aggregate
multiple sources of content including text, images, data, visualization tools,
and the like. These aggregations are an essential product of eScience, and will
become increasingly common in the age of data-driven scholarship. The OAI-ORE
specifications conform to the core concepts of the Web architecture and the
semantic Web, ensuring that applications that use them will integrate well into
the general Web environment.


  We propose a conjecture on the structure of the bounded derived category of
coherent sheaves of the moduli space rank $2$ parabolic bundles on
$\mathbb{P}^1$.


  Using the superfield formalism, we study the dynamical breaking of gauge
symmetry in the N=1 three-dimensional supersymmetric Chern-Simons model,
coupled to a complex scalar superfield with a quartic self-coupling. This is an
analogue of the conformally invariant Coleman-Weinberg model in four spacetime
dimensions. We show that a mass for the gauge and matter superfields are
dynamically generated after two-loop corrections to the effective
superpotential. We also discuss the N=2 extension of our work, showing that the
Coleman-Weinberg mechanism in such model is not feasible, because it is
incompatible with perturbation theory.


  We present a Gibbs sampler for the Dempster-Shafer (DS) approach to
statistical inference for Categorical distributions. The DS framework extends
the Bayesian approach, allows in particular the use of partial prior
information, and yields three-valued uncertainty assessments representing
probabilities "for", "against", and "don't know" about formal assertions of
interest. The proposed algorithm targets the distribution of a class of random
convex polytopes which encapsulate the DS inference. The sampler relies on an
equivalence between the iterative constraints of the vertex configuration and
the non-negativity of cycles in a fully connected directed graph. Illustrations
include the testing of independence in 2x2 contingency tables and parameter
estimation of the linkage model.


  We investigate the real-time dynamics of the half-filled one-dimensional
extended Hubbard model in the strong-coupling regime, when driven by a
transient laser pulse. Starting from a wide regime displaying a charge-density
wave in equilibrium, a robust photoinduced in-gap state appears in the optical
conductivity, depending on the parameters of the pulse. Here, by tuning its
conditions, we maximize the overlap of the time-evolving wavefunction with
excited states displaying the elusive bond-ordered wave of this model. Finally,
we make a clear connection between the emergence of this order and the
formation of the aforementioned in-gap state, suggesting the potential
observation of purely electronic (i.e., not associated with a Peierls
instability) bond-ordered waves in experiments involving molecular crystals.


  We investigate the effects of electron and acoustic-phonon confinement on the
low-field electron mobility of thin square silicon nanowires (SiNWs) that are
surrounded by SiO$_2$ and gated. We employ a self-consistent
Poisson-Schr\"{o}dinger-Monte Carlo solver that accounts for scattering due to
acoustic phonons (confined and bulk), intervalley phonons, and the Si/SiO$_2$
surface roughness. The wires considered have cross sections between 3 $\times$
3 nm$^2$ and 8 $\times$ 8 nm$^2$. For larger wires, as expected, the dependence
of the mobility on the transverse field from the gate is pronounced. At low
transverse fields, where phonon scattering dominates, scattering from confined
acoustic phonons results in about a 10% decrease of the mobility with respect
to the bulk phonon approximation. As the wire cross-section decreases, the
electron mobility drops because the detrimental increase in both
electron--acoustic phonon and electron--surface roughness scattering rates
overshadows the beneficial volume inversion and subband modulation. For wires
thinner than 5 $\times$ 5 nm$^2$, surface roughness scattering dominates
regardless of the transverse field applied and leads to a monotonic decrease of
the electron mobility with decreasing SiNWs cross section.


  Motivated by the recent results in the standard model (SM) Higgs boson search
at the Large Hadron Collider (LHC) we investigate the SM-like CP-even Higgs
boson of the U(1)'-extended minimal supersymmetric standard model (UMSSM) and
its branching ratio into the b b-bar, W W*, and \chi^0_1 \chi^0_1 modes. In the
Summer 2011, a 2 sigma excess was reported in the channel H -> W W* -> l+ nu l-
nu-bar around 130 - 140 GeV range. Later on in December 2011 announcements were
made that an excess was seen in the 124-126 GeV range, while the SM Higgs boson
above 131 GeV up to about 600 GeV is ruled out. We examine two scenarios of
these mass ranges: (i) 130 GeV < M_{h_{SM-like}} < 141 GeV and show that the
Higgs boson can decay into invisible neutralinos to evade the SM bound; and
(ii) 120 GeV < M_{h_{\rm SM-like}} < 130 GeV and show that the Higgs boson can
avoid decaying into neutralinos and thus gives enhanced rates into visible
particles. We use the \eta model of E_6 with TeV scale supersymmetry to
illustrate the idea by scanning the parameter space to realize these two
different scenarios.


  Let $A$ be a finite-dimensional algebra over a field $k$. We define $A$ to be
$\mathbf{C}$-dichotomic if it has the dichotomy property of the representation
type on complexes of projective $A$-modules. $\mathbf{C}$-dichotomy implies the
dichotomy properties of representation type on the levels of homotopy category
and derived category. If $k$ admits a finite separable field extension $K/k$
such that $K$ is algebraically closed, the real number field for example, we
prove that $A$ is $\mathbf{C}$-dichotomic. As a consequence, the second derived
Brauer-Thrall type theorem holds for $A$, i.e., $A$ is either derived discrete
or strongly derived unbounded.


  We introduce a new set of symmetries obeyed by tree-level gauge-theory
amplitudes involving at least one gluon. The symmetry acts as a
momentum-dependent shift on the color factors of the amplitude. Using the
radiation vertex expansion, we prove the invariance under this color-factor
shift of the $n$-gluon amplitude, as well as amplitudes involving massless or
massive particles in an arbitrary representation of the gauge group with spin
zero, one-half, or one. The Bern-Carrasco-Johansson relations are a direct
consequence of this symmetry.
  We also introduce the cubic vertex expansion of an amplitude, and use it to
derive a generalized-gauge-invariant constraint on the kinematic numerators of
the amplitude. We show that the amplitudes of the bi-adjoint scalar theory are
invariant under the color-factor symmetry, and use this to derive the null
eigenvectors of the propagator matrix.
  We generalize the color-factor shift to loop level, and prove the invariance
under this shift of one-loop $n$-gluon amplitudes in any theory that admits a
color-kinematic-dual representation of numerators. We show that the one-loop
color-factor symmetry implies known relations among the integrands of one-loop
color-ordered amplitudes.


  In this article, a fully discrete short pulse (SP) equation is presented as
an integrability condition of a linear system of difference equations (also
known as discrete Lax pair). Additionally, two semi-discrete versions of the SP
equation have also been obtained from fully discrete SP equation under
continuum limits. Darboux transformation is employed to compute multi-soliton
solutions of fully discrete and semi-discrete SP equations. Explicit
expressions of first and second nontrivial soliton solutions are computed. We
also derived explicit expression of breather solution for fully discrete SP
equation. The dynamics of single loop soliton and interaction mechanism of
loop-loop and loop-antiloop solutions has been explored and illustrated.


  The entropy production rate of nonequilibrium systems is studied via the
Fokker-Planck equation. This approach, based on the entropy production rate
equation given by Schnakenberg from a master equation, requires information of
the transition rate of the system under study. We obtain the transition rate
from the conditional probability extracted from the Fokker-Planck equation and
then derive a new and more operable expression for the entropy production rate.
Examples are presented as applications of our approach.


  In this paper, we introduce a new family of orthogonal systems, termed as the
M\"{u}ntz ball polynomials (MBPs), which are orthogonal with respect to the
weight function: $\|x\|^{2\theta+2\mu-2} (1-\|x\|^{2\theta})^{\alpha}$ with the
parameters $\alpha>-1, \mu>- 1/2$ and $\theta>0$ in the $d$-dimensional unit
ball $x\in {\mathbb B}^d=\big\{x\in\mathbb{R}^d: r=\|x\|\leq1\big\}$. We then
develop efficient and spectrally accurate MBP spectral-Galerkin methods for
singular eigenvalue problems including degenerating elliptic problems with
perturbed ellipticity and Schr\"odinger's operators with fractional potentials.
We demonstrate that the use of such non-standard basis functions can not only
tailor to the singularity of the solutions but also lead to sparse linear
systems which can be solved efficiently.


  Widely-used LiDAR-based 3D object detectors often neglect fundamental
geometric information readily available from the object proposals in their
confidence estimation. This is mostly due to architectural design choices,
which were often adopted from the 2D image domain, where geometric context is
rarely available. In 3D, however, considering the object properties and its
surroundings in a holistic way is important to distinguish between true and
false positive detections, e.g. occluded pedestrians in a group. To address
this, we present GACE, an intuitive and highly efficient method to improve the
confidence estimation of a given black-box 3D object detector. We aggregate
geometric cues of detections and their spatial relationships, which enables us
to properly assess their plausibility and consequently, improve the confidence
estimation. This leads to consistent performance gains over a variety of
state-of-the-art detectors. Across all evaluated detectors, GACE proves to be
especially beneficial for the vulnerable road user classes, i.e. pedestrians
and cyclists.


  We use exact diagonalization and the modified Lanczos method to study the
finite energy and finite momentum spectral weight of the longitudinal and
transverse spin excitations of the anisotropic zig-zag ladder. We find that the
spin excitations form continua of gapless or gapped spinons in the different
regions of the phase diagram. The results obtained are consistent with a
picture previously proposed that in the anisotropic case there is a transition
from a gapped regime to a gapless regime, for small interchain coupling. In
this regime we find a sharp low-energy peak in the structure function for the
transverse spin excitations, consistent with a finite stiffness.


  We build a model of information cascades on feed-based networks, taking into
account the finite attention span of users, message generation rates and
message forwarding rates. Using this model, we study through simulations, the
effect of the extent of user attention on the probability that the cascade
becomes viral. In analogy with a branching process, we estimate the branching
factor associated with the cascade process for different attention spans and
different forwarding probabilities, and demonstrate that beyond a certain
attention span, critical forwarding probabilities exist that constitute a
threshold after which cascades can become viral. The critical forwarding
probabilities have an inverse relationship with the attention span. Next, we
develop a semi-analytical approach for our model, that allows us determine the
branching factor for given values of message generation rates, message
forwarding rates and attention spans. The branching factors obtained using this
analytical approach show good agreement with those obtained through
simulations. Finally, we analyze an event specific dataset obtained from
Twitter, and show that estimated branching factors correlate well with the
cascade size distributions associated with distinct hashtags.


  Some highlights of the recent researches in the field of relativistic jets
are reviewed and critically analyzed. Given the extent of the available
literature, this essay symbolically takes the baton from the outstanding and
recent review by Blandford, Meier, and Readhead (2019). Therefore, I focus
mostly on the results published during the latest few years, with specific
reference to jets from active galactic nuclei.


  This is the first of a series of papers in which the kinematics of disk
galaxies over a range of scales is scrutinised employing spectroscopy. A
fundamental aspect of these studies is presented here: the new publicly
available software tool TiRiFiC
(http://www.astro.uni-bonn.de/~gjozsa/tirific.html) enables a direct fit of a
``tilted-ring model'' to spectroscopic data cubes. The algorithm generates
model data cubes from the tilted-ring parametrisation of a rotating disk, which
are automatically adjusted to reach an optimum fit via a chi-squared
minimisation method to an observed data cube. The structure of the new
software, the shortcomings of the previously available programs to produce a
tilted-ring model, and the performance of TiRiFiC are discussed. Our method is
less affected by the well-known problem of beam smearing that occurs when
fitting to the velocity field. Since with our method we fit many data points in
a data cube simultaneously, TiRiFiC is sensitive to very faint structures and
can hence be used to derive tilted-ring models significantly extending in
radius beyond those derived from a velocity field. The software is able to
parametrise HI disks of galaxies that are intersected by the line-of-sight
twice or more, i.e. if the disks are heavily warped, and/or with a significant
shift of the projected centre of rotation, and/or if seen edge-on. Furthermore,
our method delivers the surface-brightness profile of the examined galaxy in
addition to the orientational parameters and the rotation curve. In order to
derive kinematic and morphological models of disk galaxies, especially reliable
rotation curves, a direct-fit method as implemented in our code should be the
tool of choice.


  K2-36 is a K dwarf orbited by two small ($R_{\rm b}=1.43\pm0.08$ $R_\oplus$
and $R_{\rm c}=3.2\pm0.3$ $R_\oplus$), close-in ($a_{\rm b}$=0.022 AU and
$a_{\rm c}$=0.054 AU) transiting planets discovered by Kepler/K2. They are
representatives of two families of small planets ($R_{\rm p}$<4 $R_\oplus$)
recently emerged from the analysis of Kepler data, with likely a different
structure, composition and evolutionary pathways. We revise the fundamental
stellar parameters and the sizes of the planets, and provide the first
measurement of their masses and bulk densities, which we use to infer their
structure and composition. We observed K2-36 with the HARPS-N spectrograph over
$\sim$3.5 years, collecting 81 useful radial velocity measurements. The star is
active, with evidence for increasing levels of magnetic activity during the
observing time span. The radial velocity scatter is $\sim$17 \ms due to the
stellar activity contribution, which is much larger that the semi-amplitudes of
the planetary signals. We tested different methods for mitigating the stellar
activity contribution to the radial velocity time variations and measuring the
planet masses with good precision. We found that K2-36 is likely a $\sim$1 Gyr
old system, and by treating the stellar activity through a Gaussian process
regression, we measured the planet masses $m_{\rm b}$=3.9$\pm$1.1 $M_\oplus$
and $m_{\rm c}$=7.8$\pm$2.3 $M_\oplus$. The derived planet bulk densities
$\rho_{\rm b}$=7.2$^{+2.5}_{-2.1}$ $g/cm^{3}$ and $\rho_{\rm
c}$=1.3$^{+0.7}_{-0.5}$ $g/cm^{3}$ point out that K2-36\,b has a rocky,
Earth-like composition, and K2-36\,c is a low-density sub-Neptune. Composed of
two planets with similar orbital separations but different densities, K2-36
represents an optimal laboratory for testing the role of the atmospheric escape
in driving the evolution of close-in, low-mass planets after $\sim$1 Gyr from
their formation.


  Wetting and dewetting dynamics of simple and complex liquids is described by
kinetic equations in gradient dynamics form that incorporates the various
coupled dissipative processes in a fully thermodynamically consistent manner.
After briefly reviewing this, we also review how chemical reactions can be
captured by a related gradient dynamics description, assuming detailed balanced
mass action type kinetics. Then, we bring both aspects together and discuss
mesoscopic reactive thin-film hydrodynamics illustrated by two examples,
namely, models for reactive wetting and reactive surfactants. These models can
describe the approach to equilibrium but may also be employed to study
out-of-equilibrium dynamics. In the latter case, one breaks the gradient
dynamics form by chemostatting to obtain active systems. In this way, for
reactive wetting we recover running drops that are driven by chemically
sustained wettability gradients and for drops covered by autocatalytic reactive
surfactants we find complex forms of self-propulsion and self-excited
oscillations.


  Three bright molecular line sources in G333 have recently been shown to
exhibit signatures of infall. We describe a molecular line radiative transfer
modelling process which is required to extract the infall signature from Mopra
and Nanten2 data. The observed line profiles differ greatly between individual
sources but are reproduced well by variations upon a common unified model where
the outflow viewing angle is the most significant difference between the
sources. The models and data together suggest that the observed properties of
the high-mass star-forming regions such as infall, turbulence, and mass are
consistent with scaled-up versions of the low-mass case with turbulent
velocities that are supersonic and an order of magnitude larger than those
found in low-mass star-forming regions. Using detailed radiative transfer
modeling, we show that the G333 cores are essentially undergoing a scaled-up
version of low mass star formation. This is an extension of earlier work in
that the degree of infall and the chemical abundances are constrained by the RT
modeling in a way that is not practical with a standard analysis of
observational data. We also find high velocity infall and high infall mass
rates, possibly suggesting accelerated collapse due to external pressure.
Molecular depletion due to freeze-out onto dust grains in central regions of
the cores is suggested by low molecular abundances of several species. Strong
evidence for a local enhancement of 13C-bearing species towards the outflow
cloud cores is discussed, consistent with the presence of shocks caused by the
supersonic motions within them.


  Consider the smooth projective models C of curves y^2=f(x) with f(x) in Z[x]
monic and separable of degree 2g+1. We prove that for g >= 3, a positive
fraction of these have only one rational point, the point at infinity. We prove
a lower bound on this fraction that tends to 1 as g tends to infinity. Finally,
we show that C(Q) can be algorithmically computed for such a fraction of the
curves. The method can be summarized as follows: using p-adic analysis and an
idea of McCallum, we develop a reformulation of Chabauty's method that shows
that certain computable conditions imply #C(Q)=1; on the other hand, using
further p-adic analysis, the theory of arithmetic surfaces, a new result on
torsion points on hyperelliptic curves, and crucially the Bhargava-Gross
equidistribution theorem for nonzero 2-Selmer group elements, we prove that
these conditions are often satisfied for p=2.


  Children in a large number of international and cross-cultural families in
and outside of the US learn and speak more than one language. However, parents
often struggle to acquaint their young children with their local language if
the child spends majority of time at home and with their spoken language if
they go to daycare or school. By reviewing relevant literature about the role
of screen media content in young children's language learning, and interviewing
a subset of parents raising multilingual children, we explore the potential of
designing conversational user interfaces which can double as an assistive
language aid.We present a preliminary list of objectives to guide the the
design of conversational user interfaces dialogue for young children's
bilingual language acquisition.


  The second Painlev\'e O.D.E. $y''-xy-2y^3=0$, $x\in \mathbb{R},$ is known to
play an important role in the theory of integrable systems, random matrices,
Bose-Einstein condensates and other problems. The generalized second Painlev\'e
equation $\Delta y -x_1 y - 2 y^3=0$, $(x_1,x_2)\in \mathbb{R}^2$, is obtained
by multiplying by $-x_1$ the linear term $u$ of the Allen-Cahn equation $\Delta
u =u^3-u$. It involves a non autonomous potential $H(x_1,y)$ which is bistable
for every fixed $x_1<0$, and thus describes as the Allen-Cahn equation a phase
transition model. The scope of this paper is to construct a solution $y$
connecting along the vertical direction $x_2$, the two branches of minima of
$H$ parametrized by $x_1$. This solution plays a similar role that the
heteroclinic orbit for the Allen-Cahn equation. It is the the first to our
knowledge solution of the Painlev\'e P.D.E. both relevant from the applications
point of view (liquid crystals), and mathematically interesting.


  Randomisation is a critical tool in designing distributed systems. The common
coin primitive, enabling the system members to agree on an unpredictable random
number, has proven to be particularly useful. We observe, however, that it is
impossible to implement a truly random common coin protocol in a fault-prone
asynchronous system.
  To circumvent this impossibility, we introduce two relaxations of the perfect
common coin: (1) approximate common coin generating random numbers that are
close to each other; and (2) Monte Carlo common coin generating a common random
number with an arbitrarily small, but non-zero, probability of failure.
Building atop the approximate agreement primitive, we obtain efficient
asynchronous implementations of the two abstractions, tolerating up to one
third of Byzantine processes. Our protocols do not assume trusted setup or
public key infrastructure and converge to the perfect coin exponentially fast
in the protocol running time.
  By plugging one of our protocols for Monte Carlo common coin in a well-known
consensus algorithm, we manage to get a binary Byzantine agreement protocol
with $O(n^3 \log n)$ communication complexity, resilient against an adaptive
adversary, and tolerating the optimal number $f<n/3$ of failures without
trusted setup or PKI. To the best of our knowledge, the best communication
complexity for binary Byzantine agreement achieved so far in this setting is
$O(n^4)$. We also show how the approximate common coin, combined with a variant
of Gray code, can be used to solve an interesting problem of Intersecting
Random Subsets, which we introduce in this paper.


  The (2,2) world-sheet supersymmetric string theory is discussed from the
viewpoint of string/membrane unification. The effective field theory in the
closed string target space is known to be the 2+2 dimensional (integrable)
theory of self-dual gravity (SDG). A world-volume supersymmetrization of the
Pleba'nski action for SDG naturally implies the maximal N=8 world-volume
supersymmetry, while the maximal supersymmetrization of the dual covariant
K"ahler-Lorentz-Chern-Simons action for SDG implies gauging a self-dual part of
the super-Lorentz symmetry in 2+10 dimensions. The proposed OSp(32|1)
supersymmetric action for the M-brane may be useful for a fundamental
formulation of uncompactified F theory, with the self-duality being playing the
central role both in the world-volume and in the target space of the M-brane.


  Several models for type Ia-like supernovae events rely on the production of a
self-sustained detonation powered by nuclear reactions. In the absence of
hydrogen, the fuel that powers these detonations typically consists of either
pure helium (He) or a mixture of carbon and oxygen (C/O). Studies that
systematically determine the conditions required to initiate detonations in C/O
material exist, but until now no analogous investigation of He matter has been
conducted. We perform one-dimensional reactive hydrodynamical simulations at a
variety of initial density and temperature combinations and find critical
length scales for the initiation of He detonations that range between 1 -
$10^{10}$ cm. A simple estimate of the length scales over which the total
consumption of fuel will occur for steady-state detonations is provided by the
Chapman-Jouguet (CJ) formalism. Our initiation lengths are consistently smaller
than the corresponding CJ length scales by a factor of $\Sim 100$, providing
opportunities for thermonuclear explosions in a wider range of low-mass white
dwarfs (WDs) than previously thought possible. We find that virialized WDs with
as little mass as 0.24 $M_\odot$ can be detonated, and that even less massive
WDs can be detonated if a sizable fraction of their mass is raised to a higher
adiabat. That the initiation length is exceeded by the CJ length implies that
certain systems may not reach nuclear statistical equilibrium within the time
it takes a detonation to traverse the object. In support of this hypothesis, we
demonstrate that incomplete burning will occur in the majority of He WD
detonations and that $^{40}$Ca, $^{44}$Ti, or $^{48}$Cr, rather than $^{56}$Ni,
is the predominant burning product for many of these events. We anticipate that
...


  The diffuse Galactic synchrotron emission should exhibit a low level of
diffuse circular polarization (CP) due to the circular motions of the emitting
relativistic electrons. This probes the Galactic magnetic field in a similar
way as the product of total Galactic synchrotron intensity times Faraday depth.
We use this to construct an all sky prediction of the so far unexplored
Galactic CP from existing measurements. This map can be used to search for this
CP signal in low frequency radio data even prior to imaging. If detected as
predicted, it would confirm the expectation that relativistic electrons, and
not positrons, are responsible for the Galactic radio emission. Furthermore,
the strength of real to predicted circular polarization would provide
statistical information on magnetic structures along the line-of-sights.


  Rhombohedral-stacked few-layer graphene (FLG) has been receiving an
ever-increasing attention owing to its peculiar electronic properties that
could lead to enticing phenomena such as superconductivity and magnetic
ordering. Up to now, experimental studies on such material have been mainly
limited by the difficulty in isolating it in thickness exceeding 3 atomic
layers with device-compatible size. In this work, rhombohedral graphene with
thickness up to 9 layers and areas up to ~50 micrometers square is grown via
chemical vapor deposition (CVD) on suspended Cu foils and transferred onto
target substrates via etch-free delamination. The domains of rhombohedral FLG
are identified by Raman spectroscopy and are found to alternate with domains of
Bernal-stacked FLG within the same crystal in a stripe-like configuration. A
combined analysis of micro-Raman mapping, atomic force microscopy and optical
microscopy indicates that the formation of rhombohedral-stacked FLG is strongly
correlated to the copper substrate morphology. Cu step bunching results in
bending of FLG and interlayer displacement along preferential crystallographic
orientations, as determined experimentally by electron microscopy, thus
inducing the stripe-like domains. The growth and transfer of rhombohedral FLG
with the reported thickness and size shall facilitate the observation of
predicted unconventional physics and ultimately add to its technological
relevance.


  We measure the transport properties of two-dimensional ultracold Fermi gases
during transverse demagnetization in a magnetic field gradient. Using a
phase-coherent spin-echo sequence, we are able to distinguish bare spin
diffusion from the Leggett-Rice effect, in which demagnetization is slowed by
the precession of spin current around the local magnetization. When the
two-dimensional scattering length is tuned to be comparable to the inverse
Fermi wave vector $k_F^{-1}$, we find that the bare transverse spin diffusivity
reaches a minimum of $1.7(6)\hbar/m$, where $m$ is the bare particle mass. The
rate of demagnetization is also reflected in the growth rate of the s-wave
contact, observed using time-resolved spectroscopy. At unitarity, the contact
rises to $0.28(3) k_F^2$ per particle, measuring the breaking of scaling
symmetry. Our observations support the conjecture that in systems with strong
scattering, the local relaxation rate is bounded from above by $k_B T/\hbar$.


  This review considers the properties of classical solutions to supergravity
theories with partially unbroken supersymmetry. These solutions saturate
Bogomol'ny-Prasad-Sommerfield bounds on their energy densities and are the
carriers of the $p$-form charges that appear in the supersymmetry algebra. The
simplest such solutions have the character of $(p+1)$-dimensional
Poincar\'e-invariant hyperplanes in spacetime, i.e. $p$-branes. Topics covered
include the relations between mass densities, charge densities and the
preservation of unbroken supersymmetry; interpolating-soliton structure;
diagonal and vertical Kaluza-Klein reduction families; multiple-charge
solutions and the four D=11 elements; duality-symmetry multiplets; charge
quantisation; low-velocity scattering and the geometry of worldvolume
supersymmetric $\sigma$-models; and the target-space geometry of BPS instanton
solutions obtained by the dimensional reduction of static $p$-branes.


  Semantic segmentation consists in classifying each pixel of an image by
assigning it to a specific label chosen from a set of all the available ones.
During the last few years, a lot of attention shifted to this kind of task.
Many computer vision researchers tried to apply autoencoder structures to
develop models that can learn the semantics of the image as well as a low-level
representation of it. In an autoencoder architecture, given an input, an
encoder computes a low dimensional representation of the input that is then
used by a decoder to reconstruct the original data. In this work, we propose an
ensemble of convolutional neural networks (CNNs). In ensemble methods, many
different models are trained and then used for classification, the ensemble
aggregates the outputs of the single classifiers. The approach leverages on
differences of various classifiers to improve the performance of the whole
system. Diversity among the single classifiers is enforced by using different
loss functions. In particular, we present a new loss function that results from
the combination of Dice and Structural Similarity Index. The proposed ensemble
is implemented by combining different backbone networks using the DeepLabV3+
and HarDNet environment. The proposal is evaluated through an extensive
empirical evaluation on two real-world scenarios: polyp and skin segmentation.
All the code is available online at https://github.com/LorisNanni.


  Quantum computing is a promising technology that harnesses the peculiarities
of quantum mechanics to deliver computational speedups for some problems that
are intractable to solve on a classical computer. Current generation noisy
intermediate-scale quantum (NISQ) computers are severely limited in terms of
chip size and error rates. Shallow quantum circuits with uncomplicated
topologies are essential for successful applications in the NISQ era. Based on
matrix analysis, we derive localized circuit transformations to efficiently
compress quantum circuits for simulation of certain spin Hamiltonians known as
free fermions. The depth of the compressed circuits is independent of
simulation time and grows linearly with the number of spins. The proposed
numerical circuit compression algorithm behaves backward stable and scales
cubically in the number of spins enabling circuit synthesis beyond
$\mathcal{O}(10^3)$ spins. The resulting quantum circuits have a simple
nearest-neighbor topology, which makes them ideally suited for NISQ devices.


  Let $X$ be a finite set in the Euclidean space $\mathbb{R}^d$. If any squared
distance of two distinct points in $X$ is an odd integer, then the cardinality
of $X$ is bounded above by $d+2$. Rosenfeld (1997) proved that there exists
$(d+2)$-point $X$ in $\mathbb{R}^d$ having only odd integral squared distances
if and only if $d+2$ is congruent to $0$ modulo $4$. The distances can be
interpreted as an element of the field $\mathbb{Z}/2\mathbb{Z}$. We generalize
this result for a local ring $(A_\mathfrak{p},\mathfrak{p}A_\mathfrak{p})$ as
follows. Let $K$ be an algebraic number field that can be embedded into
$\mathbb{R}$. Fix an embedding of $K$ into $\mathbb{R}$, and $K$ is interpreted
as a subfield of $\mathbb{R}$. Let $A=\mathcal{O}_K$ be the ring of integers of
$K$, and $\mathfrak{p}$ a prime ideal of $\mathcal{O}_K$. Let
$(A_\mathfrak{p},\mathfrak{p}A_\mathfrak{p})$ be the local ring obtained from
the localization $(A\setminus \mathfrak{p})^{-1} A$, which is interpreted as a
subring of $\mathbb{R}$. If the squared distances of $X\subset \mathbb{R}^d$
are in $A_\mathfrak{p}$ and each squared distance is congruent to some constant
$k \not\equiv 0 $ modulo $\mathfrak{p} A_\mathfrak{p}$, then $|X| \leq d+2$. In
this paper, we prove that there exists a set $X\subset \mathbb{R}^d$ attaining
the upper bound $|X| \leq d+2$ if and only if $d+2$ is congruent to $0$ modulo
$4$ when the field $A_\mathfrak{p}/ \mathfrak{p} A_\mathfrak{p}$ is of
characteristic 2, and $d+2$ is congruent to $0$ modulo $p$ when
$A_\mathfrak{p}/ \mathfrak{p} A_\mathfrak{p}$ is of characteristic $p$ odd. We
also construct examples attaining this upper bound.


  Two-way microwave-optical quantum transduction is an essential capability to
connect distant superconducting qubits via optical fiber, and to enable quantum
networking at a large scale. In Bl\'esin, Tian, Bhave, and Kippenberg's
article, ``Quantum coherent microwave-optical transduction using high overtone
bulk acoustic resonances" (Phys. Rev. A, 104, 052601 (2021)), they lay out a
quantum transduction system that accomplishes this by combining a piezoelectric
interaction to convert microwave photons to GHz-scale phonons, and an
optomechanical interaction to up-convert those phonons into telecom-band
photons using a pump laser set to an adjacent telecom-band tone. In this work,
we discuss these coupling interactions from first principles in order to
discover what device parameters matter most in determining the transduction
efficiency of this new platform, and to discuss strategies toward system
optimization for near-unity transduction efficiency, as well as how noise
impacts the transduction process.
  In addition, we address the post-transduction challenge of separating single
photons of the transduced light from a classically bright pump only a few GHz
away in frequency by proposing a novel optomechanical coupling mechanism using
phonon-photon four-wave mixing via stress-induced optical nonlinearity and its
thermodynamic connection to higher-orders of electrostriction. Where this
process drives transduction by consuming pairs instead of individual pump
photons, it will allow a clean separation of the transduced light from the
classically bright pump driving the transduction process.


  In 1932 Ettore Majorana published an article proving that relativity allows
any value for the spin of a quantum particle and that there is no privilege for
the half integer spin. The Majorana idea was so innovative for the time that
the scientific community understood its importance only towards the end of the
thirties. This paper aims to highlight the depth of the scientific thought of
Majorana that, well in advance of its time, opened the way for modern particle
physics and introduced for the first time the idea of a universal quantum
equation, able to explain the behavior of particles with arbitrary spin and of
any nature, regardless the value of their speed. It will be analyzed in detail
and made explicit all the steps that lead to the physical mathematical
formulation of the Majorana theory. A part of these steps require basic
knowledge of quantum physics but not for this should be regarded as trivial
since they show the physical meaning hidden into the structure of the equation.
Moreover, the explicit method for the construction of the infinite matrices
will be given, by which the infinite components of the wave functions
representing the fundamental and excited states of the particle are calculated.


  In the COVID-19 pandemic, billions are wearing face masks, in both health
care settings and in public. Which type of mask we should wear in what
situation, is therefore important. There are three basic types: cotton,
surgical, and respirators (e.g. FFP2, N95 and similar). All are essentially air
filters worn on the face. Air filtration is relatively well understood,
however, we have almost no direct evidence on the relative role played by
aerosol particles of differing sizes in disease transmission. But if the virus
concentration is assumed independent of aerosol particle size, then most virus
will be in particles > 1 $\mu$m. We develop a model that predicts surgical
masks are effective at reducing the risk of airborne transmission because the
filtering material most surgical masks use is highly effective at filtering
particles with diameters > 1 $\mu$m. However, surgical masks are significantly
less effective than masks of FFP2, N95 and similar standards, mostly due to the
poor fit of surgical masks. Earlier work found that ~30% of the air bypasses a
surgical mask and is not filtered. This highlights the fact that standards for
surgical masks do not specify how well the mask should fit, and so are not
adequate for protection against COVID-19.


  Let $\mathfrak a$ be an algebraic Lie algebra. An adapted pair for $\mathfrak
a$ is pair $(h,\eta)$ consisting of an ad-semisimple element of $h \in
\mathfrak a$ and a regular element of $\eta \in \mathfrak a^*$ satisfying $(ad
\ h)\eta=-\eta$. An adapted pair $(h,\eta)$ is said to satisfy integrality if
$ad \ h$ has integer eigenvalues on $\mathfrak a$. Integrality is shown to hold
for any Frobenius Lie algebra which is a biparabolic subalgebra of a semisimple
Lie algebra; but may fail in general.
  Call $\mathfrak a$ regular if there are no proper semi-invariant polynomial
functions on $\mathfrak a^*$ and if the subalgebra of invariant functions is
polynomial. In this case there are no known counter-examples to integrality. It
is shown that if $\mathfrak a$ is the canonical truncation of a biparabolic
subalgebra of a simple Lie algebra $\mathfrak g$ which is regular and admits an
adapted pair $(h,\eta)$, then the eigenvalues of $ad \ h$ on $\mathfrak a$ lie
in $\frac{1}{m}\mathbb Z$, where $m$ is a coefficient of a simple root in the
highest root of $\mathfrak g$.
  Let $\mathfrak a$ be a regular Lie algebra admitting an adapted pair
$(h,\eta)$. Let $\mathfrak a_\mathbb Z$ be the subalgebra spanned by the
eigensubspaces of $ad \ h$ with integer eigenvalue. It is shown that the
canonical truncation of $\mathfrak a_\mathbb Z$ is regular. Sufficient
knowledge of the relation between the generators for the invariant polynomial
functions on $\mathfrak a^*$ and on $\mathfrak a^*_\mathbb Z$ can then lead to
establishing the integrality of $(h,\eta)$. This method is used to show the
integrality of an adapted pair for a truncated parabolic subalgebra of a simple
Lie algebra of type $C$.


  A scalar gravity model is developed according the 'geometric conventionalist'
approach introduced by Poincare (Einstein 1921, Poincare 1905, Reichenbach
1957, Gruenbaum1973). In principle this approach allows an alternative
interpretation and formulation of General Relativity Theory (GRT), with
distinct i) physical congruence standard, and ii) gravitation dynamics
according Hamilton-Lagrange mechanics, while iii) retaining empirical
indistinguishability with GRT. In this scalar model the congruence standards
have been expressed as gravitationally modified Lorentz Transformations
(Broekaert 2002). The first type of these transformations relate quantities
observed by gravitationally 'affected' (natural geometry) and 'unaffected'
(coordinate geometry) observers and explicitly reveal a spatially variable
speed of light (VSL). The second type shunts the unaffected perspective and
relates affected observers, recovering i) the invariance of the locally
observed velocity of light, and ii) the local Minkowski metric (Broekaert
2003). In the case of a static gravitation field the model retrieves the
phenomenology implied by the Schwarzschild metric. The case with proper source
kinematics is now described by introduction of a 'sweep velocity' field w: The
model then provides a hamiltonian description for particles and photons in full
accordance with the first Post-Newtonian approximation of GRT (Weinberg 1972,
Will 1993).


  Several authors have recently considered the smallest positive part missing
from an integer partition, known as the minimum excludant or mex. In this work,
we revisit and extend connections between Dyson's crank statistics, the mex,
and Frobenius symbols, with a focus on combinatorial proof techniques. One
highlight is a generating function expression for the number of partitions with
a bounded crank that does not include an alternating sum. This leads to a
combinatorial interpretation involving types of Durfee rectangles.


  We calculate the amplitude for a non-excited closed string with nonzero
winding number to scatter from a D-string with a near critical E field. We go
to the NCOS limit and observe that we get the same result if we adopt another
approach put forward by Gomis and Ooguri.


  Containerization allows bundling applications and their dependencies into a
single image. The containerization framework Docker eases the use of this
concept and enables sharing images publicly, gaining high momentum. However, it
can lead to users creating and sharing images that include private keys or API
secrets-either by mistake or out of negligence. This leakage impairs the
creator's security and that of everyone using the image. Yet, the extent of
this practice and how to counteract it remains unclear.
  In this paper, we analyze 337,171 images from Docker Hub and 8,076 other
private registries unveiling that 8.5% of images indeed include secrets.
Specifically, we find 52,107 private keys and 3,158 leaked API secrets, both
opening a large attack surface, i.e., putting authentication and
confidentiality of privacy-sensitive data at stake and even allow active
attacks. We further document that those leaked keys are used in the wild: While
we discovered 1,060 certificates relying on compromised keys being issued by
public certificate authorities, based on further active Internet measurements,
we find 275,269 TLS and SSH hosts using leaked private keys for authentication.
To counteract this issue, we discuss how our methodology can be used to prevent
secret leakage and reuse.


  Let $F$ be a non-archimedean local field of characteristic different from $2$
and $G$ be either an odd special orthogonal group ${\rm SO}_{2r+1}(F)$ or a
symplectic group ${\rm Sp}_{2r}(F)$. In this paper, we establish the local
converse theorem for $G$. Namely, for given two irreducible admissible generic
representations of $G$ with the same central character, if they have the same
local gamma factors twisted by irreducible supercuspidal representations of
${\rm GL}_n(F)$ for all $1 \leq n \leq r$ with the same additive character,
these representations are isomorphic. Using the theory of Cogdell, Shahidi, and
Tsai on partial Bessel functions and the classification of irreducible generic
representations, we break the barrier on the rank of twists $1 \leq n \leq
2r-1$ in the work of Jiang and Soudry, and extend the result of Q. Zhang, which
was achieved for all supercuspidal representations in characteristic $0$.


  I present asymmetric orientifold models which, with the addition of RR
fluxes, fix all the NS NS moduli including the dilaton. In critical string
theory, this gives new AdS backgrounds with (discretely tunably) weak string
coupling. Extrapolating to super-critical string theory, this construction
leads to a promising candidate for a metastable de Sitter background with
string coupling of order 1/10 and dS radius of order 100 times the string
scale. Extrapolating further to larger and larger super-critical dimension
suggests the possibility of finding de Sitter backgrounds with weaker and
weaker string coupling. This note is an updated version of the last part of my
Strings 2001 talk.


  We describe and motivate three goals for the screen display of asynchronous
text deliberation pertaining to a document: (1) visibility of relationships
between comments and the text they reference, between different comments, and
between group members and the document and discussion, and (2)
distinguishability of boundaries between contextually related and unrelated
text and comments and between individual authors of documents and comments.
Interfaces for document-centered discussion generally fail to fulfill one or
both of these goals as well as they could. We describe the design of the new
version of Deme, a Web-based platform for online deliberation, and argue that
it achieves the two goals better than other recent designs.


  We study a construction, which produces surfaces $Y \subset P_3$ with cusps.
For example we obtain surfaces of degree six with 18, 24 or 27 three-divisible
cusps. For sextic surfaces in a particular family of up to 30 cusps the codes
of these sets of cusps are determined explicitly.


  Finetuning Pretrained Language Models (PLM) for IR has been de facto the
standard practice since their breakthrough effectiveness few years ago. But, is
this approach well understood? In this paper, we study the impact of the
pretraining collection on the final IR effectiveness. In particular, we
challenge the current hypothesis that PLM shall be trained on a large enough
generic collection and we show that pretraining from scratch on the collection
of interest is surprisingly competitive with the current approach. We benchmark
first-stage ranking rankers and cross-encoders for reranking on the task of
general passage retrieval on MSMARCO, Mr-Tydi for Arabic, Japanese and Russian,
and TripClick for specific domain. Contrary to popular belief, we show that,
for finetuning first-stage rankers, models pretrained solely on their
collection have equivalent or better effectiveness compared to more general
models. However, there is a slight effectiveness drop for rerankers pretrained
only on the target collection. Overall, our study sheds a new light on the role
of the pretraining collection and should make our community ponder on building
specialized models by pretraining from scratch. Last but not least, doing so
could enable better control of efficiency, data bias and replicability, which
are key research questions for the IR community.


  Wu showed that certain sums of products of binomial coefficients modulo 2 are
given by the run length transforms of several famous linear recurrence
sequences, such as the positive integers, the Fibonacci numbers, the extended
Lucas numbers, and Narayana's cows sequence. In this paper we show that the run
length transform of such sequences are 2-regular sequences. This allows us to
obtain Wu's results and some new ones using the computer program Walnut,
eliminating the need for long technical proofs.


  The paper studies Hausdorff-Young inequalities for certain group extensions,
by use of Mackey's theory. We consider the case in which the dual action of the
quotient group is free almost everywhere. This result applies to yield a
Hausdorff-Young inequality for nonunimodular groups.


  The conclusions of randomized controlled trials may be biased when the
outcome of one unit depends on the treatment status of other units, a problem
known as interference. In this work, we study interference in the setting of
one-sided bipartite experiments in which the experimental units - where
treatments are randomized and outcomes are measured - do not interact directly.
Instead, their interactions are mediated through their connections to
interference units on the other side of the graph. Examples of this type of
interference are common in marketplaces and two-sided platforms. The
cluster-randomized design is a popular method to mitigate interference when the
graph is known, but it has not been well-studied in the one-sided bipartite
experiment setting. In this work, we formalize a natural model for interference
in one-sided bipartite experiments using the exposure mapping framework. We
first exhibit settings under which existing cluster-randomized designs fail to
properly mitigate interference under this model. We then show that minimizing
the bias of the difference-in-means estimator under our model results in a
balanced partitioning clustering objective with a natural interpretation. We
further prove that our design is minimax optimal over the class of linear
potential outcomes models with bounded interference. We conclude by providing
theoretical and experimental evidence of the robustness of our design to a
variety of interference graphs and potential outcomes models.


  In this paper, we develop fast algorithms for two stochastic submodular
maximization problems. We start with the well-studied adaptive submodular
maximization problem subject to a cardinality constraint. We develop the first
linear-time algorithm which achieves a $(1-1/e-\epsilon)$ approximation ratio.
Notably, the time complexity of our algorithm is $O(n\log\frac{1}{\epsilon})$
(number of function evaluations) which is independent of the cardinality
constraint, where $n$ is the size of the ground set. Then we introduce the
concept of fully adaptive submodularity, and develop a linear-time algorithm
for maximizing a fully adaptive submoudular function subject to a partition
matroid constraint. We show that our algorithm achieves a
$\frac{1-1/e-\epsilon}{4-2/e-2\epsilon}$ approximation ratio using only
$O(n\log\frac{1}{\epsilon})$ number of function evaluations.


  In this paper we study the regularity properties of solutions to the
Davey-Stewartson system. It is shown that for initial data in a Sobolev space,
the nonlinear part of the solution flow resides in a smoother space than the
initial data for all times. We also obtain that the Sobolev norm of the
nonlinear part of the evolution grows at most polynomially. As an application
of the smoothing estimate, we study the long term dynamics of the forced and
weakly damped Davey-Stewartson system. In this regard we give a new proof for
the existence and smoothness of the global attractors in the energy space.


  We study the effect of perpendicular magnetic fields on a single-electron
system with a strongly time-dependent electrostatic potential. Continuous
improvements to the current quantization in these electron pumps are revealed
by high-resolution measurements. Simulations show that the sensitivity of
tunnel rates to the barrier potential is enhanced, stabilizing particular
charge states. Nonadiabatic excitations are also suppressed due to a reduced
sensitivity of the Fock-Darwin states to electrostatic potential. The
combination of these effects leads to significantly more accurate current
quantization.


  We proposed the agent-based model of financial markets where agents (or
traders) are represented by three-state spins located on the plane lattice or
social network. The spin variable represents only the individual opinion
(advice) that each trader gives to his nearest neighbors. In the model the
agents can be considered as cunning. For instance, although agent having
currently a maximal value of the spin advises his nearest neighbors to buy some
stocks he, perfidiously, will sell some stocks in the next Monte Carlo step or
will occupy a neutral position. In general, the trader has three possibilities:
he can buy some stocks if his opinion change within a single time step is
positive, sell some stocks if this change is negative, or remain inactive if
his opinion is unchanged. The predictions of our model, found by simulations,
well agree with the empirical universal distribution of interoccurrence times
between daily losses below negative thresholds following the Tsallis
q-exponential.


  Contrary to mechanical waves, the two-slit interference experiment of single
photons shows that the behavior of classical electromagnetic waves corresponds
to the quantum mechanical one of single photons, which is also different from
the quantum-field-theory behavior such as the creations and annihilations of
photons, the vacuum fluctuations, etc. Owing to a purely quantum effect,
quantum tunneling particles including tunneling photons (evanescent modes) can
propagate over a spacelike interval without destroying causality. With this
picture we conclude that the superluminality of evanescent modes is a quantum
mechanical rather than a classical phenomenon.


  The theory of General Relativity has successfully passed a large number of
observational tests. The theory has been extensively tested in the weak-field
regime with experiments in the Solar System and observations of binary pulsars.
The past five years have seen significant advancements in the study of the
strong-field regime, which can now be tested with gravitational waves, X-ray
data, and mm Very Long Baseline Interferometry observations. Here I summarize
the state-of-the-art of the tests of General Relativity with black hole X-ray
data, discussing its recent progress and future developments.


  We study the strong rates of the Euler-Maruyama approximation for one
dimensional stochastic differential equations whose drift coefficient may be
neither continuous nor one-sided Lipschitz and diffusion coefficient is
H\"older continuous. Especially, we show that the strong rate of the
Euler-Maruyama approximation is 1/2 for a large class of equations whose drift
is not continuous. We also provide the strong rate for equations whose drift is
H\"older continuous and diffusion is nonconstant


  CCD was born in Bell Laboratories in 1969 and has been widely used in various
fields. Its ultra-low noise and high quantum efficiency make it work well in
particle physics, high energy physics, nuclear physics and astrophysics.
Nowadays, more and more CCD cameras have been developed for medical diagnosis,
scientific experiments, aerospace, military exploration and other fields. For
the wide range of CCD cameras, a Non-vacuum-cooling compact (NVCC) scientific
CCD camera has been developed, including FPGA-based low noise clock and bias
driver circuit, data acquisition circuit, STM32-based temperature control
design. At the same time, the readout noise of the imaging system is studied
emphatically. The scheme to generate the CCD clock and the bias driving circuit
through ultralow noise LDOs is proposed. The camera was tested in a variety of
environments, and the test results show that the system can run at a maximum
rate of 5M pixels/s and readout noise is as low as 9.29e^- when the CCD readout
speed is 500K pixels/s. Finally, a series of stability tests were carried out
on the camera system.


  This paper presents a general model for calculating the density of states and
the Cooper pair potential in proximity coupled superconducting bi- and
tri-layer films. The typical example of superconducting tunnel junctions is
used to show that the model is working.


  For a $C^2$ function $u$ and an elliptic operator $L$, we prove a
quantitative estimate for the derivative $du$ in terms of local bounds on $u$
and $Lu$. An integral version of this estimate is then used to derive a
condition for the zero-mean value property of $\Delta u$. An extension to
differential forms is also given. Our approach is probabilistic and could
easily be adapted to other settings.


  Path integral techniques and Green functions formalism are applied to study
the (time) temperature dependent scattering of a polaronic quasiparticle by a
local anharmonic potential in a bath of diatomic molecules. The electrical
resistivity has been computed in any molecular lattice dimensionality for
different values of electron-phonon coupling and intermolecular forces. A broad
resistivity peak with non metallic behavior at temperatures larger than $\simeq
100K$ is predicted by the model for sufficiently strong polaron-local potential
coupling strengths. This peculiar behavior, ascribed to purely structural
effects, is favoured in low dimensionality.


  Different aspects of the predictability problem in dynamical systems are
reviewed. The deep relation among Lyapunov exponents, Kolmogorov-Sinai entropy,
Shannon entropy and algorithmic complexity is discussed. In particular, we
emphasize how a characterization of the unpredictability of a system gives a
measure of its complexity. Adopting this point of view, we review some
developments in the characterization of the predictability of systems showing
different kind of complexity: from low-dimensional systems to high-dimensional
ones with spatio-temporal chaos and to fully developed turbulence. A special
attention is devoted to finite-time and finite-resolution effects on
predictability, which can be accounted with suitable generalization of the
standard indicators. The problems involved in systems with intrinsic randomness
is discussed, with emphasis on the important problems of distinguishing chaos
from noise and of modeling the system. The characterization of irregular
behavior in systems with discrete phase space is also considered.


  We propose a new formula for the star product in deformation quantization of
Poisson structures related in a specific way to a variational problem for a
function $S$, interpreted as the action functional. Our approach is motivated
by perturbative Algebraic Quantum Field Theory (pAQFT). We provide a direct
combinatorial formula for the star product and we show that it can be applied
to a certain class of infinite dimensional manifolds (e.g., regular observables
in pAQFT). This is the first step towards understanding how pAQFT can be
formulated such that the only formal parameter is $\hbar$, while the coupling
constant can be treated as a number.
  In the introductory part of the paper, apart from reviewing the framework, we
make precise several statements present in the pAQFT literature and recast
these in the language of (formal) deformation quantization. Finally, we use our
formalism to streamline the proof of perturbative agreement provided by Drago,
Hack, and Pinamonti and to generalize some of the results obtained in that work
to the case of a non-linear interaction.


  A detailed understanding of energy transduction is crucial for achieving
precise control of energy flow in complex, integrated systems. In this context,
carbon nanotubes (CNTs) are intriguing model systems due to their rich,
chirality-dependent electronic and optical properties. Here, we study the
quenching of fluorescence from isolated quantum dots (QDs) upon approach of
individual CNTs attached to atomic force microscope probes. Precision
measurements of many different CNT/QD pairs reveal behavior consistent with
resonant energy transfer between QD and CNT excitons via a Fohrster-like
dipole-dipole coupling. The data reveal large variations in energy transfer
length scales even though peak efficiencies are narrowly distributed around
96%. This saturation of efficiency is maintained even when energy transfer must
compete with elevated intrinsic non-radiative relaxation rates during QD aging.
These observations suggest that excitons can be created at different locations
along the CNT length, thereby resulting in self-limiting behavior.


  The reduction of quantum scattering leads to the suppression of shot noise.
In the present paper, we analyze the crossover from the quantum transport
regime with universal shot noise, to the classical regime where noise vanishes.
By making use of the stochastic path integral approach, we find the statistics
of transport and the transmission properties of a chaotic cavity as a function
of a system parameter controlling the crossover. We identify three different
scenarios of the crossover.


  Although recent measurements of the shower profiles of ultra-high energy
cosmic rays suggest that they are largely initiated by heavy nuclei, such
conclusions rely on hadronic interaction models which have large uncertainties.
We investigate an alternative test of cosmic ray composition which is based on
the observation of ultra-high energy photons produced through cosmic ray
interactions with diffuse low energy photon backgrounds during intergalactic
propagation. We show that if the ultra-high energy cosmic rays are dominated by
heavy nuclei, the flux of these photons is suppressed by approximately an order
of magnitude relative to the proton-dominated case. Future observations by the
Pierre Auger Observatory may be able to use this observable to constrain the
composition of the primaries, thus providing an important cross-check of
hadronic interaction models.


  The nonlinear optical properties and electro-optic effects of some
oxygen-octahedric ferroelectrics are studied by the density functional theory
(DFT) in the local density approximation (LDA) expressions based on first
principle calculations without the scissor approximation. We present
calculations of the frequency- dependent complex dielectric function and the
second harmonic generation response coefficient
\c{hi}(2)(-2{\omega},{\omega},{\omega}) over a large frequency range in
tetragonal and rhombohedral phases. The electronic linear electrooptic
susceptibility \c{hi}(2) (-{\omega},{\omega},0) is also evaluated below the
band gap. These results are based on a series of the LDA calculation using DFT.
Results for \c{hi}(2) (-{\omega},{\omega},0) are in agreement with the
experiment below the band gap and those for
\c{hi}(2)(-2{\omega},{\omega},{\omega}) are compared with the experimental data
where available.


  Group and individual solutions are considered for hard problems such as
satisfiability problem. Time-space trade-off in a structured active memory
provides means to achieve lower time complexity for solutions of these
problems.


  We report the discovery of two new types of variability in the neutron star
low-mass X-ray binary MXB 1730-335 (the 'Rapid Burster'). In one observation in
1999, it exhibits a large-amplitude quasi-periodic oscillation with a period of
about 7 min. In another observation in 2008, it exhibits two 4-min long 75 per
cent deep dips 44 min apart. These two kinds of variability are very similar to
the so-called $\rho$ or 'heartbeat' variability and the $\theta$ variability,
respectively, seen in the black hole low-mass X-ray binaries GRS 1915+105 and
IGR J17091-3624. This shows that these types of behavior are unrelated to a
black hole nature of the accretor. Our findings also show that these kinds of
behaviour need not take place at near-Eddington accretion rates. We speculate
that they may rather be related to the presence of a relatively wide orbit with
an orbital period in excess of a few days and about the relation between these
instabilities and the type II bursts.


  We formulate a generalization of the Glauber formalism for hadron-nucleus and
nucleus-nucleus collisions based on the Pomeron approach to high energy
interactions. Our treatment is based on two physical assumptions (i.e. two
small parameters) : (i) that only sufficiently small distances contribute to
the Pomeron structure; and (ii) the triple Pomeron vertex $G_{3P}/g_{P-N}
  \ll 1$ (where $g_{P-N}$ is the Pomeron-nucleon vertex) is small. A systematic
method is developed for calculating the total, elastic and diffractive
dissociation cross sections as well as the survival probability of large
rapidity gap processes and inclusive observables, both for hadron - nucleus and
nucleus-nucleus collisions. Our approach suggests saturation of the density of
the produced hadrons in nucleus-nucleus collisions, the value of the saturation
density turns out to be large and depends on the number of nucleons in the
lightest nucleus.


  We search for the rare flavor-changing neutral current process $B^- \to
\Lambda {\overline p} \nu{\overline{\nu}}$ using data from the BABAR
experiment. A total of 424 fb$^{-1}$ of $e^+e^-$ collision data collected at
the center-of-mass energy of the $\Upsilon$(4S) resonance is used in this
study, corresponding to a sample of ${(471 \pm 3) \times 10^{6}}$
$B\overline{B}$ pairs. Signal $B^- \to \Lambda {\overline p}
\nu{\overline{\nu}}$ candidates are identified by first fully reconstructing a
$B^+$ decay in one of many possible exclusive decays to hadronic final states,
then examining detector activity that is not associated with this reconstructed
$B^+$ decay for evidence of a signal $B^- \to \Lambda {\overline p}
\nu{\overline{\nu}}$ decay. The data yield is found to be consistent with the
expected background contribution under a null signal hypothesis, resulting in
an upper limit of ${{\cal B} (B^- \to \Lambda {\overline p}
\nu{\overline{\nu}}) < 3.0\times 10^{-5}}$ at the $90\%$ confidence level.


  While misinformation and disinformation have been thriving in social media
for years, with the emergence of the COVID-19 pandemic, the political and the
health misinformation merged, thus elevating the problem to a whole new level
and giving rise to the first global infodemic. The fight against this infodemic
has many aspects, with fact-checking and debunking false and misleading claims
being among the most important ones. Unfortunately, manual fact-checking is
time-consuming and automatic fact-checking is resource-intense, which means
that we need to pre-filter the input social media posts and to throw out those
that do not appear to be check-worthy. With this in mind, here we propose a
model for detecting check-worthy tweets about COVID-19, which combines deep
contextualized text representations with modeling the social context of the
tweet. We further describe a number of additional experiments and comparisons,
which we believe should be useful for future research as they provide some
indication about what techniques are effective for the task. Our official
submission to the English version of CLEF-2020 CheckThat! Task 1, system
Team_Alex, was ranked second with a MAP score of 0.8034, which is almost tied
with the wining system, lagging behind by just 0.003 MAP points absolute.


  Safe, environmentally conscious and flexible, these are the central
requirements for the future mobility. In the European border region between
Germany, France and Luxembourg, mobility in the world of work and pleasure is a
decisive factor. It must be simple, affordable and available to all. The
automation and intelligent connection of road traffic plays an important role
in this. Due to the distributed settlement structure with many small towns and
village and a few central hot spots, a fully available public transport is very
complex and expensive and only a few bus and train lines exist. In this
context, the trinational research project TERMINAL aims to establish a
cross-border automated minibus in regular traffic and to explore the user
acceptance for commuter traffic. Additionally, mobility on demand services are
tested, and both will be embedded within the existing public transport
infrastructure.


  Let c denote a non-negative constant. Suppose that we are given an
edge-weighted bipartite graph G=(V,E) with its 2-layered drawing and a family X
of intersecting edge pairs. We consider the problem of finding a maximum
weighted matching M* such that each edge in M* intersects with at most c other
edges in M*, and that all edge crossings in M* are contained in X. In the
present paper, we propose polynomial-time algorithms for the cases of c=1 and
2. The time complexities of the algorithms are O((k+m)log n+n) for c=1 and
O(k^3+k^2n+m(m+log n)) for c=2, respectively, where n=|V|, m=|E| and k=|X|.


  In this article we show that finite perturbative corrections in
non-supersymmetric strings can be understood via an interplay between modular
invariance and misaligned supersymmetry. While modular invariance is known to
be crucial in closed-string models, its presence and role for open strings is
more subtle. Nevertheless, we argue that it leads to cancellations in physical
quantities such as the one-loop cosmological constant and prevents them from
diverging. In particular, we show that if the sector-averaged number of states
does not grow exponentially, as predicted by misaligned supersymmetry, all
exponential divergences in the one-loop cosmological constant cancel out as
well. To account for the absence of power-law divergences, instead, we need to
resort to the modular structure of the partition function. We finally comment
on the presence of misaligned supersymmetry in the known 10-dimensional
tachyon-free non-supersymmetric string theories.


  An 1D tight-binding version of the Dirac equation is considered; after
checking that it recovers the usual discrete Schr?odinger equation in the
nonrelativistic limit, it is found that for two-valued Bernoulli potentials the
zero mass case presents absence of dynamical localization for specific values
of the energy, albeit it has no continuous spectrum. For the other energy
values (again excluding some very specific ones) the Bernoulli Dirac system is
localized, independently of the mass.


  This manuscript has been accepted for publication in Physical Review Fluids,
see
https://journals.aps.org/prfluids/accepted/d5074S28J6b11905012b7cb06505e8f2149dd5f20.
  This work investigates the mechanisms that underlie transitions to turbulence
in a three-dimensional domain in which the variation of flow quantities in the
out-of-plane direction is much weaker than any in-plane variation. This is
achieved using a model for the quasi-two-dimensional magnetohydrodynamic flow
in a duct with moving lateral walls and an orthogonal magnetic field. In this
environment, conventional subcritical routes to turbulence, which are highly
three-dimensional, are prohibited. To elucidate the remaining mechanisms
involved in quasi-two-dimensional turbulent transitions, the magnetic field
strength and degree of antisymmetry in the base flow are varied, the latter via
the relative motion of the lateral duct walls. Introduction of any amount of
antisymmetry to the base flow drives the critical Reynolds number infinite, as
the TS instabilities take on opposite signs of rotation, and destructively
interfere. However, an increasing magnetic field strength limits interaction
between the instabilities, permitting finite critical Reynolds numbers. The
transient growth only mildly depends on the base flow, with negligible
differences for friction parameters $H \gtrsim 30$. Direct numerical
simulations, initiated with random noise, indicate that for $H \leq 1$,
supercritical exponential growth leads to saturation, but not turbulence. For
higher $3 \leq H \leq 10$, a turbulent transition occurs, and is maintained at
$H=10$. For $H \geq 30$, the turbulent transition still occurs, but is short
lived, as the turbulent state quickly collapses. In addition, for $H \geq 3$,
an inertial subrange is identified, with the perturbation energy exhibiting a
$-5/3$ power law dependence on wave number.


  The success of state-of-the-art deep neural networks heavily relies on the
presence of large-scale labelled datasets, which are extremely expensive and
time-consuming to annotate. This paper focuses on tackling semi-supervised part
segmentation tasks by generating high-quality images with a pre-trained GAN and
labelling the generated images with an automatic annotator. In particular, we
formulate the annotator learning as a learning-to-learn problem. Given a
pre-trained GAN, the annotator learns to label object parts in a set of
randomly generated images such that a part segmentation model trained on these
synthetic images with their predicted labels obtains low segmentation error on
a small validation set of manually labelled images. We further reduce this
nested-loop optimization problem to a simple gradient matching problem and
efficiently solve it with an iterative algorithm. We show that our method can
learn annotators from a broad range of labelled images including real images,
generated images, and even analytically rendered images. Our method is
evaluated with semi-supervised part segmentation tasks and significantly
outperforms other semi-supervised competitors when the amount of labelled
examples is extremely limited.


  The Spitzer spectrum of the giant FR II radio galaxy 3C 326 is dominated by
very strong molecular hydrogen emission lines on a faint IR continuum. The H2
emission originates in the northern component of a double-galaxy system
associated with 3C 326. The integrated luminosity in H2 pure-rotational lines
is 8.0E41 erg/s, which corresponds to 17% of the 8-70 micron luminosity of the
galaxy. A wide range of temperatures (125-1000 K) is measured from the H2 0-0
S(0)-S(7) transitions, leading to a warm H2 mass of 1.1E9 Msun. Low-excitation
ionic forbidden emission lines are consistent with an optical LINER
classification for the active nucleus, which is not luminous enough to power
the observed H2 emission. The H2 could be shock-heated by the radio jets, but
there is no direct indication of this. More likely, the H2 is shock-heated in a
tidal accretion flow induced by interaction with the southern companion galaxy.
The latter scenario is supported by an irregular morphology, tidal bridge, and
possible tidal tail imaged with IRAC at 3-9 micron. Unlike ULIRGs, which in
some cases exhibit H2 line luminosities of comparable strength, 3C 326 shows
little star-formation activity (~0.1 Msun/yr). This may represent an important
stage in galaxy evolution. Starburst activity and efficient accretion onto the
central supermassive black hole may be delayed until the shock-heated H2 can
kinematically settle and cool


  In a previous work and in terms of an exact quantum-mechanical framework,
$\hbar$-independent causal and retarded expectation values of the
second-quantized electro-magnetic fields in the Coulomb gauge were derived in
the presence of a conserved classical electric current. The classical
$\hbar$-independent Maxwell's equations then naturally emerged. In the present
work, we extend these considerations to linear gravitational quantum deviations
around a flat Minkowski space-time in a Coulomb-like gauge. The emergence of
the classical causal and properly retarded linearized classical theory of
general relativity with a conserved classical energy-momentum tensor is then
outlined. The quantum-mechanical framework also provides for a simple approach
to classical quadrupole gravitational radiation of Einstein and microscopic
spontaneous graviton emission and/or absorption processes.


  The CACTUS experiment recently observed a gamma ray excess above 50 GeV from
the direction of the Draco dwarf spheroidal galaxy. Considering that Draco is
dark matter dominated the gamma rays may be generated through dark matter
annihilation in the Draco halo. In the framework of the minimal supersymmetric
extension of the standard model we explore the parameter space to account for
the gamma ray signals at CACTUS. We find that the neutralino mass is
constrained to be approximately in the range between 100 GeV ~ 400 GeV and a
sharp central cuspy of the dark halo profile in Draco is necessary to explain
the CACTUS results. We then discuss further constraints on the supersymmetric
parameter space by observations at the ground based ARGO detector. It is found
that the parameter space can be strongly constrained by ARGO if no excess from
Draco is observed above 100 GeV.


  We present the observational results of a survey designed to target and
detect asteroids whose colors are similar to those of Vesta family members and
thus may be considered as candidates for having a basaltic composition. Fifty
basaltic candidates were selected with orbital elements that lie outside of the
Vesta dynamical family. Optical and near-infrared spectra were used to assign a
taxonomic type to 11 of the 50 candidates. Ten of these were spectroscopically
confirmed as V-type asteroids, suggesting that most of the candidates are
basaltic and can be used to constrain the distribution of basaltic material in
the Main Belt.
  Using our catalog of V-type candidates and the success rate of the survey, we
calculate unbiased size-frequency and semi-major axis distributions of V-type
asteroids. These distributions, in addition to an estimate for the total mass
of basaltic material, suggest that Vesta was the predominant contributor to the
basaltic asteroid inventory of the Main Belt, however scattered planetesimals
from the inner Solar System (a < 2.0 AU) and other partially/fully
differentiated bodies likely contributed to this inventory. In particular, we
infer the presence of basaltic fragments in the vicinity of asteroid 15
Eunomia, which may be derived from a differentiated parent body in the middle
Main Belt (2.5 < a < 2.8). We find no asteroidal evidence for a large number of
previously undiscovered basaltic asteroids, which agrees with previous theories
suggesting that basaltic fragments from the ~100 differentiated parent bodies
represented in meteorite collections have been "battered to bits" [Burbine,
T.H., Meibom, A., Binzel, R.P., 1996. Mantle material in the Main Belt:
Battered to bits? Met. & Planet. Sci. 31, 607].


  We study the 2D linear stability analysis of a deformable solid of a finite
height $H$, steadily sliding on top of a rigid solid within a generic
rate-and-state friction type constitutive framework, fully accounting for
elastodynamic effects. We derive the linear stability spectrum, quantifying the
interplay between stabilization related to the frictional constitutive law and
destabilization related both to the elastodynamic bi-material coupling between
normal stress variations and interfacial slip, and to finite size effects. The
stabilizing effects related to the frictional constitutive law include
velocity-strengthening friction (i.e.~an increase in frictional resistance with
increasing slip velocity, both instantaneous and under steady-state conditions)
and a regularized response to normal stress variations. We first consider the
small wave-number $k$ limit and demonstrate that homogeneous sliding in this
case is universally unstable, independently of the details of the friction law.
This universal instability is mediated by propagating waveguide-like modes,
whose fastest growing mode is characterized by a wave-number satisfying $k
H\!\sim\!{\cal O}(1)$ and by a growth rate that scales with $H^{-1}$. We then
consider the limit $k H\!\to\!\infty$ and derive the stability phase diagram in
this case. We show that the dominant instability mode travels at nearly the
dilatational wave-speed in the opposite direction to the sliding direction.
Instability modes which travel at nearly the shear wave-speed in the sliding
direction also exist in some range of physical parameters. Finally, we show
that a finite-time regularized response to normal stress variations, within the
framework of generalized rate-and-state friction models, tends to promote
stability.


  In the framework of canonical seesaw model, we present a simple but viable
scenario to explicitly break an $S^{}_{3{\rm L}} \times S^{}_{3{\rm R}}$ flavor
symmetry in the leptonic sector. It turns out that the leptonic flavor mixing
matrix is completely determined by the mass ratios of charged leptons (i.e.,
$m^{}_e/m^{}_\mu$ and $m^{}_\mu/m^{}_\tau$) and those of light neutrinos (i.e.,
$m^{}_1/m^{}_2$ and $m^{}_2/m^{}_3$). The latest global-fit results of three
neutrino mixing angles $\{\theta^{}_{12}, \theta^{}_{13}, \theta^{}_{23}\}$ and
two neutrino mass-squared differences $\{\Delta m^2_{21}, \Delta m^2_{31}\}$ at
the $3\sigma$ level are used to constrain the parameter space of
$\{m^{}_1/m^{}_2, m^{}_2/m^{}_3\}$. The predictions for the mass spectrum and
flavor mixing are highlighted: (1) The neutrino mass spectrum shows a
hierarchical pattern and a normal ordering, e.g., $m^{}_1 \approx 2.2~{\rm
meV}$, $m^{}_2 \approx 8.8~{\rm meV}$ and $m^{}_3 \approx 52.7~{\rm meV}$; (2)
Only the first octant of $\theta^{}_{23}$ is allowed, namely, $41.8^\circ
\lesssim \theta^{}_{23} \lesssim 43.3^\circ$; (3) The Dirac CP-violating phase
$\delta \approx -22^\circ$ deviates significantly from the maximal value
$-90^\circ$. All these predictions are ready to be tested in the ongoing and
forthcoming neutrino oscillation experiments. Moreover, we demonstrate that the
cosmological matter-antimatter asymmetry can be explained via resonant
leptogenesis, including the individual lepton-flavor effects. In our scenario,
the leptonic CP violation at low- and high-energy scales are closely connected.


  This document presents the syntax, classification rules, realizability
semantics, and soundness theorem for Cedille, an extrinsic (i.e., Curry-style)
type theory extending the Calculus of Constructions, and designed for deriving
of inductive datatypes, with their induction principles.


  In order to bring artificial agents into our lives, we will need to go beyond
supervised learning on closed datasets to having the ability to continuously
expand knowledge. Inspired by a student learning in a classroom, we present an
agent that can continuously learn by posing natural language questions to
humans. Our agent is composed of three interacting modules, one that performs
captioning, another that generates questions and a decision maker that learns
when to ask questions by implicitly reasoning about the uncertainty of the
agent and expertise of the teacher. As compared to current active learning
methods which query images for full captions, our agent is able to ask pointed
questions to improve the generated captions. The agent trains on the improved
captions, expanding its knowledge. We show that our approach achieves better
performance using less human supervision than the baselines on the challenging
MSCOCO dataset.


  We study the Josephson plasma resonance (JPR) in
Bi$_2$Sr$_2$CaCu$_2$O$_{8+y}$ (BSCCO) with spatially dependent interlayer-phase
coherence (IPC). The half-irradiated BSCCO (HI-BSCCO), in which columnar
defects are introduced only in a half of the sample, shows several resonance
peaks, which are not simple superposition of the peaks in irradiated- and
pristine-parts. JPR in HI-BSCCO changes its character from irradiated- to
pristine-type at a crossover frequency ($\omega_{cr}$). We demonstrate that the
one-dimensional \LSGE, which takes into account the spatial dependence of IPC,
can reproduce most of the experimental findings including the presence of
$\omega_{cr}$.


  We investigate the predicted present-day temperature profiles of the hot,
X-ray emitting gas in galaxy clusters for two cosmological models - a current
best-guess LCDM model and standard cold dark matter (SCDM). Our
numerically-simulated "catalogs" of clusters are derived from high-resolution
(15/h kpc) simulations which make use of a sophisticated, Eulerian-based,
Adaptive Mesh-Refinement (AMR) code that faithfully captures the shocks which
are essential for correctly modelling cluster temperatures. We show that the
temperature structure on Mpc-scales is highly complex and non-isothermal.
However, the temperature profiles of the simulated LCDM and SCDM clusters are
remarkably similar and drop-off as $T +AFw-propto (1+-r/a_x)^{-+AFw-delta}$
where $a_x +AFw-sim r_{vir}/1.5$ and $+AFw-delta +AFw-sim 1.6$. This decrease
is in good agreement with the observational results of Markevitch et al.(1998)
but diverges, primarily in the innermost regions, from their fit which assumes
a polytropic equation of state. Our result is also in good agreement with a
recent sample of clusters observed by BeppoSAX though there is some indication
of missing physics at small radii ($r<0.2 r_{vir}$). We discuss the
interpretation of our results and make predictions for new x-ray observations
that will extend to larger radii than previously possible. Finally, we show
that, for $r>0.2 r_{vir}$, our universal temperature profile is consistent with
our most recent simulations which include both radiative cooling and supernovae
feedback.


  When a black-box optimization objective can only be evaluated with costly or
noisy measurements, most standard optimization algorithms are unsuited to find
the optimal solution. Specialized algorithms that deal with exactly this
situation make use of surrogate models. These models are usually continuous and
smooth, which is beneficial for continuous optimization problems, but not
necessarily for combinatorial problems. However, by choosing the basis
functions of the surrogate model in a certain way, we show that it can be
guaranteed that the optimal solution of the surrogate model is integer. This
approach outperforms random search, simulated annealing and one Bayesian
optimization algorithm on the problem of finding robust routes for a
noise-perturbed traveling salesman benchmark problem, with similar performance
as another Bayesian optimization algorithm, and outperforms all compared
algorithms on a convex binary optimization problem with a large number of
variables.


  We study the statistics of infima, stopping times and passage probabilities
of entropy production in nonequilibrium steady states, and show that they are
universal. We consider two examples of stopping times: first-passage times of
entropy production and waiting times of stochastic processes, which are the
times when a system reaches for the first time a given state. Our main results
are: (i) the distribution of the global infimum of entropy production is
exponential with mean equal to minus Boltzmann's constant; (ii) we find the
exact expressions for the passage probabilities of entropy production to reach
a given value; (iii) we derive a fluctuation theorem for stopping-time
distributions of entropy production. These results have interesting
implications for stochastic processes that can be discussed in simple colloidal
systems and in active molecular processes. In particular, we show that the
timing and statistics of discrete chemical transitions of molecular processes,
such as, the steps of molecular motors, are governed by the statistics of
entropy production. We also show that the extreme-value statistics of active
molecular processes are governed by entropy production, for example, the
infimum of entropy production of a motor can be related to the maximal
excursion of a motor against the direction of an external force. Using this
relation, we make predictions for the distribution of the maximum backtrack
depth of RNA polymerases, which follows from our universal results for
entropy-production infima.


  This paper introduces a set of algorithms for Monte-Carlo Bayesian
reinforcement learning. Firstly, Monte-Carlo estimation of upper bounds on the
Bayes-optimal value function is employed to construct an optimistic policy.
Secondly, gradient-based algorithms for approximate upper and lower bounds are
introduced. Finally, we introduce a new class of gradient algorithms for
Bayesian Bellman error minimisation. We theoretically show that the gradient
methods are sound. Experimentally, we demonstrate the superiority of the upper
bound method in terms of reward obtained. However, we also show that the
Bayesian Bellman error method is a close second, despite its significant
computational simplicity.


  We propose through first-principles investigation that GaTeCl monolayer is an
excellent two-dimensional multiferroics with giant mechanical anisotropy and
ferroelasticity. The calculated phonon spectrum, molecular dynamic simulations,
and elastic modules confirm its stability, and our cleavage energy analysis
shows that exfoliating one GaTeCl monolayer from the GaTeCl bulk is feasible.
The calculated in-plane ferroelectric polarization reaches to 578 pC/m. The
energy barriers per formula unit of the ferroelastic rotational and
ferroelectric reversal transitions are 476.2 meV and 754.1 meV, respectively,
which are the greatest in the two-dimensional multiferroics family so far, and
makes the GaTeCl monolayer have robust ferroelasticity and ferroelectricity
under room temperature. Uniaxial stress along the polarization direction can
make the indirect gap transit to direct gap. Furthermore, the GaTeCl monolayer
has giant piezoelectricity and optical second harmonic generation, especially
for the range of visible light. These interesting mechanical, electronic, and
optical properties of the GaTeCl monolayer show its great potential for
multi-functional devices and nonlinear optoelectronic applications.


  We propose generalization of escape rate from a metastable state for
externally driven correlated noise processes in one dimension. In addition to
the internal non-Markovian thermal fluctuations, the external correlated noise
processes we consider are Gaussian, stationary in nature and are of
Ornstein-Uhlenbeck type. Based on a Fokker-Planck description of the effective
noise processes with finite memory we derive the generalized escape rate from a
metastable state in the moderate to large damping limit and investigate the
effect of degree of correlation on the resulting rate. Comparison of the
theoretical expression with numerical simulation gives a satisfactory agreement
and shows that by increasing the degree of external noise correlation one can
enhance the escape rate through the dressed effective noise strength.


  Hair cells of the auditory and vestibular systems display astonishing
sensitivity, frequency selectivity, and temporal resolution to external
signals. These specialized cells utilize an internal active amplifier to
achieve highly sensitive mechanical detection. One of the manifestations of
this active process is the occurrence of spontaneous limit-cycle motion of the
hair cell bundle. As hair bundles under in vivo conditions are typically
coupled to each other by overlying structures, we explore the role of this
coupling on the dynamics of the system, using a combination of theoretical and
experimental approaches. Our numerical model suggests that the presence of
chaotic dynamics in the response of individual bundles enhances their ability
to synchronize when coupled, resulting in significant improvement in the
system's ability to detect weak signals. This synchronization persists even for
a large frequency dispersion and a large number of oscillators comprising the
system. Further, the amplitude and coherence of the active motion is not
reduced upon increasing the number of oscillators. Using artificial membranes,
we impose mechanical coupling on groups of live and functional hair bundles,
selected from in vitro preparations of the sensory epithelium, allowing us to
explore the role of coupling experimentally. Consistent with the numerical
simulations of the chaotic system, synchronization occurs even for large
frequency dispersion and a large number of hair cells. Further, the amplitude
and coherence of the spontaneous oscillations are independent of the number of
hair cells in the network. We therefore propose that hair cells utilize their
chaotic dynamics to stabilize the synchronized state and avoid the amplitude
death regime, resulting in collective coherent motion that could play a role in
generating spontaneous otoacoustic emissions and an enhanced ability to detect
weak signals.


  The B[e]/K binary system MWC 623 was reinvestigated using new spectroscopic
observations. The absorption lines of the K and the B star do not exhibit any
significant radial velocity variations over a time interval of 14 years. The
spectral classification using a recent echelle spectrum yielded spectral types
of K2II-Ib and B4III. The luminosity class of the K star gives an estimate of
the distance towards MWC 623 of 2.4(+1.4/-0.9) kpc. This is consistent with the
kinematic distance of 2.0(+0.6/-0.3) kpc. The masses derived from the locations
of the binary components in the H-R diagram are 7+-1.5 Msun and 7.5+-2.5 Msun
for the B and K star, respectively, i.e. the mass ratio is close to 1. Both
stars are coeval with an age of 50+10/-20 Myr as shown by the comparison with
isochrones. The high luminosity of the K star excludes a pre-main sequence
evolutionary phase as explanation for the strong LiI lambda 6708 absorption
line observed in the late-type component. Rather, the high lithium abundance is
a consequence of the young age. Likewise, the B[e] star is a slightly evolved
object starting it post-main sequence evolution.


  In this note, we propose to use TasTas \cite{shi2020speech} for the
end-to-end approach to monaural speech separation in the pre-cocktail party
problem. Our experiments on the public WSJ0-5mix data corpus results in 10.41dB
SDR improvement. If online voice data remixing augmentation
\cite{zeghidour2020wavesplit} is adopted in training, an 11.14dB SDR
improvement can be achieved. We have open-sourced our re-implementation of the
DPRNN-TasNet in
https://github.com/ShiZiqiang/dual-path-RNNs-DPRNNs-based-speech-separation,
and our TasTas is realized based on this implementation of DPRNN-TasNet, it is
believed that the results in this paper can be reproduced with ease.


  We investigate the required peripheral circuits to enable ideal performance
for a high-gain travelling-wave parametric amplifier (TWPA) based on three-wave
mixing (3WM). By embedding the TWPA in a network of superconducting diplexers,
hybrid couplers and impedance matching networks, the amplifier can deliver a
high stable gain with near-quantum-limited noise performance, with suppressed
gain ripples, while eliminating the reflections of the signal, the idler and
the pump as well as the transmission of all unwanted tones. We also demonstrate
a configuration where the amplifier can isolate. We call this technique
Wideband Idler Filtering (WIF). The theory is supported by simulations that
predict over 20 dB gain in the 4-8 GHz band with 10 dB isolation for a single
amplifier and 30 dB isolation for two cascaded amplifiers. We demonstrate how
the WIF-TWPAs can be used to construct controllable isolators with over 40 dB
isolation over the full 4-8 GHz band.


  Aims. We analyse SUMER spectral scans of a large sunspot within active region
NOAA 10923, obtained on 14-15 November 2006, to determine the morphology and
dynamics of the sunspot atmosphere at different heights/temperatures. Methods:
The data analysed here consist of spectroheliograms in the continuum around
142.0 nm and in the Si iv 140.2 nm, O iii 70.3 nm, N iv 76.5 nm, and O iv 79.0
nm spectral lines. Gaussian-fitting of the observed profiles provides
line-of-sight velocity and Doppler-width maps. Results: The data show an
asymmetric downflow pattern compatible with the presence of the inverse
Evershed flow in a region within roughly twice the penumbral radius at
transition-region temperatures up to 0.18 MK. The motions, highly inhomogeneous
on small scales, seem to occur in a collar of radially directed filamentary
structures, with an average width less than the 1 Mm spatial resolution of
SUMER and characterised by different plasma speeds. Assuming that the flows are
directed along the field lines, we deduce that such field lines are inclined by
10 deg to 25 deg with respect to the solar surface.